


One Bright Day In The Middle Of The Night

by orphan_account



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Dad Sans, Dimension Travel, Frisk Is Dead, Mute Frisk, Other, Past Child Abuse, Protective Sans, Skeleton Frisk, Underfell Sans, no one is happy except maybe frisk, undertale meets underfell
Language: English
Status: In-Progress
Published: 2016-04-14
Updated: 2016-06-06
Packaged: 2018-06-02 04:00:43
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 12
Words: 22,626
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6549865
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: <blockquote class="userstuff">
              <p>This is a combination of several AUs; Underfell, Pacifist Frisk Death/Skeleton Frisk, Dad Sans, Timeline Jumping Sans. During a pacifist run in Underfell Frisk is murdered by Undyne and awakens from death as a baby bones skeleton without any of their save/reset powers. With their Flowey back in the claws of Alpyhs, Papyrus absolutely livid, and Toriel still locked in the ruins Frisk is left in the care of only Sans. Sans spirited Frisk away and began to dimension hop with Frisk, looking for their lost powers and meeting alternate versions of themselves. On hiatus.</p>
            </blockquote>





	1. Family Reunion

**Author's Note:**

> Woo sudden idea for a story and I can't work it into my comic so here it goes. I need more skeleton Frisk and dad Sans in my life. How many chapters will there be? Who knows.

Undyne shifted in her armor, squirming a little to get the hot metal off her skin as she crossed the land bridge back to Waterfall. She felt uncomfortable with her choice to let the human go and wander around Hotland but . . . she couldn’t find it in herself to wish she had attacked them again. They were . . . more like a monster than she had expected. Or maybe more like a hero from one of Alphy’s anime heros. The rest of her guards knew what to do and if they set a toe out of line Undyne would be there in a second to rip them into tiny shreds. 

She sighed as she pulled her helmet back on and stomped directly into the deep pools of waterfall, swimming even faster than she could run at full sprint. It felt good to be back in the water and Undyne could have sworn that the metal around her skin was actually steaming. 

She twisted through the water, dodging debris as she swam and popping above water only to wave half-heartedly at passing monsters. She just wanted to go home and sit for a while, think about what she was really expecting to happen. What she would do as Head of the Royal Guard – what she should do as Undyne – Once the human reached King Asgore. Undyne could not, would not, allow any harm to come to her King no matter how good willed the human was. 

With a deep sign, Undyne pulled herself out of the softly glowing blue water and shook herself. She was deep in the waterfall now, bathed in the soft gleam of iridescent mushrooms and the soft smell of musty water filled her gills. Undyne stretched out and cracked her spine before she began to stomp up the dry path to her house, ignoring the shy ghost that vanished up the path to his own home before she could greet him. If Nabstablook didn’t want to speak to anyone without his cousins about Undyne certainly wasn’t the one who would warm him up. 

It was only about halfway up to her house that a bellow made her jump out of her scales. “UNDYNE! MY DEAR FRIEND! I HAVE NEWS OF THE HUMAN!” 

“Oh?” Undyne asked as Papyrus skidded to a haul ticking up soft mud and almost tripping over his own gangly legs. 

“YES! I HAVE WORD THAT THEY ARE WEARING AN OLD APRON! NOT A TUTU AS I HAD TOLD YOU BEFORE! NYEHEHEHEHEHEHEHE!” Papyrus declared. 

“Oh?” Undyne asked again as she grabbed Papyrus around the neck and held his skull to her chest so she could give him a noogie. Papyrus squeezed his eye sockets shit and squirmed but he wasn’t nearly strong enough to escape the headlock of a buff fish. “Yeah right, ya punk! I already saw the human and they weren’t wearing either of those things.” 

“Y-YOU DID?” Papyrus asked, suddenly freezing. 

“Yeah. And, uh, I think I get why you said . . . you know. They don’t seem that bad,” Undyne said. If anyone would understand it would be Papyrus and when he looked at her his eyesockets were sparkling. “They’re still a human. But I think I get why you were so against killing the-yeep!” Undyne just about yanked Papyrus’ arm off as he escaped from her headlock and wrapped her in such a strong hug that she was lifted off the ground. 

Papyrus was laughing in her fin, and she kicked uselessly at open air as he spun her around. “OH I KNEW YOU WOULD SPARE THEM! I DID TOO, THEY LIKED MY SPAGETTI AND THEY LIKED MY PUZZLES!” He set her down and she stumbled slightly, summoning a glowing spear to stick into the mud and steady herself. Papyrus was gushing, babbling about how she could be such good friends with the human and something about a date when a flicker of red caught Undyne’s eye.

In a dark corner of the waterfall, deep in a small sea of gently straying reeds there was a flicker of crimson. The color of Determination. Undyne’s posture slowly stiffened as the red hint of magic flickered and went out like a dying ember before it appeared again, struggling not to be snuffed out completely. It seemed to pulse a little stronger between each flicker and as Undyne watched the faint light, while defiantly magic, seemed more like a machine than anything organic. “Papyrus?” Undyne said, grabbing his elbow and giving him a little shake. 

Papyrus paused in the middle of a story and looked where Undyne pointed. “Do you see that?” She asked. 

Before Papyrus could respond there was a sudden, defined crackle of dark red that oddly resembled a fist going through rice paper. There was a loud cry followed by a thump and the furious rustle of flora as the red light of magic fade away completely. Undyne wrapped her hand around her spear and kicked off before Papyrus could stop her. The human? Had they followed her!? Undyne roughly tore the reeds apart, looking for the glowing red heart that would give Frisk away when she instead came across a tiny ball of trembling, black fabric. 

At the sound of Undyne’s violent approach the dark ball of fabric let out a small whimper as it flipped over. It was . . . a tiny skeleton. Tiny, even smaller than Sans was and Undyne drew back with a sharp inhale as Papyrus ran up behind her. A tiny skeleton with a gleaming white skull and two small pinpricks of light in in its sockets that flickered weakly as tears welled up in its empty eyes. It had a detached jaw, pulled up into a permanent smile even as it shook in confusion and fear at the armored woman wielding a spear before it. It was dressed strangely, wearing a striped shirt that marked all children in the underground – a pale off white with gold stripes and little black shorts. I’s tiny feet shook in untied red and black sneakers and the whole of the skeleton seemed to be drowning in a massively oversized black jacket. It was so large that Undyne could not see their hands out the sleeves and their skull seemed to be almost buried in a hood of soft pink fur. 

“O-oh. Oh shit! I’m so sorry!” Undyne said. She reeled back as her spear vanished so the tiny skeleton would see that she meant no harm before she leaned forward to touch them. The skeleton was shaking like a leaf, and for some reason they shook even more furiously as she reached for them. 

Odd, children always seemed to love Undyne. That was all she had time to think before the was another furious blaze of scarlet magic and an animal skull slammed down over the little skeleton, caging the little one in massive jaws. The animal skull produced a dull, throaty hum and a single eye socket glowed a violent red, charged with so much magic that it made the base of Undyne’s spine prickle. 

Papyrus was beside her, one arm around her and pulling her back a little, away from the jaws of the blaster. When she glanced at him she could see recognition in his eyes mixed with a blaze of confusion. Undyne blinked and growled as she yanked free of him and glared up at the blaster. There was no way a kid could do this, so what-!?

She had only seen him teleport once before, suddenly appearing at his station with a hotdog and completely nonchalant about it. It had surprised her then and it surprised her now to look up and see a pair of fuzzy pink slippers planted firmly on the head of the blaster. He wasn’t dressed right, his pants were black and gold instead of the usual black and white and he wore only a red t-shirt, his jacket on the child in his blaster’s fangs. He was grinning wide, and a single gold tooth glistened in the light of the red magic that consumed the whole left side of his face. 

“hey,” Sans growled, his voice filled with such hate that Undyne took a step back and Papyrus took a step forward. Sans snarled wordlessly at his brother and he hunched his shoulders like some predatory cat about to pounce. “i’m in a good mood right now, so i’ll give you five seconds to tell me why the fuck you pointed a spear at my kid.” There was a whirr as two more blasters formed behind him, balls of light already forming in their jaws as they prepared to fire. “before i rip you to shreds."


	2. Bad Blood

**Notes for the Chapter:**

> Underfell is 2 edgy but god do I love it. There's not much to say about it so let's get it going!

Undyne and Papyrus stared at Sans for a long moment, both struggling to process the information presented to them. It was Undyne who ultimately responded first, curling her face up into a snarl under her helmet. “Is that some kind of joke?” She spat and Sans flinched. For a moment he looked surprised and confused, as though he had not realized Undyne was the one in the armour. 

Then he just looked enraged. “what the fuck, boss!?” Sans demanded as he turned his blazing red gaze onto his brother. “why are you with her? ” he spat ‘her’ like it was snake venom, and from the way he crinkled his forehead it was clear that he was very tempted to set off his blasters without waiting for an answer. 

“SANS,” Papyrus said, folding his arms over his chest and looking indignant, “WHAT HAS GOTTEN INTO YOU, SANS? WHY IS YOUR EYE RED?” Sans bristled and put a skeleton hand to his eye. Red? It had always been red! “AND YOU CANT JUST SAY CHILDREN ARE YOURS EITHER, WHERE DID YOU FIND THAT SKELETON?” 

“are you trying to imply something?” Sans demanded haughtily. 

“SANS YOU HAVE TO GIVE THAT CHILD BACK TO THEIR PARENTS!” 

“i am their parents!” Sans clenched his hands into fists. Okay, so, first of all fuck this universe. What was wrong with Papyrus? He was talking to Sans like he was a young child! Sans preferred his jackass of a Papyrus far more than this one. “get the fuck away from us,” he spat. 

“Enough!” Undyne finally lost it, and she swung her spear at Sans before he had time to react, turning his soul green and locking him into place. Sans lashed out with a snarl, turning both Undyne and Papyrus red with little fanfare and forcing them down, putting such a great pressure on them that Undyne sank down to her thighs in the soft waterfall dirt and Papyrus fell on his face. 

“you sons of bitches, you’re not hurting my baby bones again.” Undyne met Sans’ eyes and was stunned at how gleeful he looked. If this was some sort of sick joke it had gone on far too long. Undyne struggled in the mud, working out her knees and then her calves against the impossible weight of her red-stained soul. She managed to free one foot before the blasters went off. 

It made a sound like a distant earthquake. 

Everything went blindingly white.

“well this is new,” said Sans. His blasters were barely formed after the blast they had taken, large chunks of hardened magic peeled and flaked away before they dissolved entirely, leaving Undyne panting heavily on her feet and Sans supporting a very confused Papyrus. The green-souled Sans snarled wordlessly as he struggled to move and attack his counterpart. 

“i’m gonna fuck you up!” Sans declared. 

“no you won’t,” the other one said flatly. “pap are you okay? he didn’t manage to hurt you, did he?”

“NO BROTHER, I AM FINE. BUT I DID NOT REALIZE THERE WERE TWO OF YOU.” Papyrus said, “THIS IS GOOD! I LOVE HAVING SANS!”

“hey shut the fuck up!” Sans snarled as he wriggled furiously on the blaster that was still protectively over his child. 

Undyne finally tore her helmet off completely and glared furiously between the two Sans’, the one who had attacked her fully intent to murder her and his own brother and the one who had just expressed an entirely unnatural strength in protecting them. This had wrong written all over it, but the Sans in blue was clearly the Sans she had known, regardless of his sudden change in power. She stood shoulder to shoulder with him, spear in each hand. “I don’t know who you are,” Undyne spat, furious that this Sans look-alike, “but you attacked a member of the Royal Guard!”

“you attacked my kid!

“I’m placing you under arrest!” Undyne twirled her spears before she launched both of them at the not-Sans, only to have them shattered by two massive bone attacks. He turned her red again and with a jerk of one hand he sent her flying across the room, slamming her violently into the far cavern wall. 

“UNDYNE! STOP, WE CAN TALK-” Papyrus shouted but it was useless. Undyne was already lunging forward, using the thrust of her own magic spear to launch herself at Sans. She sent a barrage of spears at him – if his blasters had shown her anything it was that he was more than capable of taking the hits. And he did. He didn’t use another one of his freakish red blasters but he hurled bone attack after bone attack at her spears to deflect them, too distracted to turn Undyne red again.   
“UNDYNE!” Papyrus cried frantically as blue jacket Sans switched from supporting his brother to holding him back.

“undyne – uh – other me!” Sans said but he went ignored as well. Undyne threw a series of yellow spears mixed with red ones at him and from the surprised noise Sans made it was safe to say he was unfamiliar with this particular attack. Sans formed a bone weapon in his hands and began to use it as a club, swinging wildly and furiously at every spear as he struggled to form a blaster overhead. Not that it mattered, Sans was fully aware that his counterpart was more than capable of combatting his blasters. 

It wasn’t until Undyne suddenly changed Sans’ soul from green back to white that the skeleton finally slipped, one foot sliding off his blaster as a yellow spear raced for his left temple. Sans didn’t have time to scream or even defend himself. He just closed his eye sockets and braced to die for real and forever. 

THUNK was the sound of spear hitting bone.

Sans opened his eyes and saw Undyne, her mouth open. Beyond her, Sans had let go of Papyrus but both skeletons weren’t moving. Time slowed all at once as Sans turned his head and saw Frisk. His Frisk. All bare bones and dark clothing, cutest thing Sans had ever seen. Their arms were spread wide and their head was thrown up to protect as much as Sans as their tiny frame could. And . . . there was a great long spear rammed through their ribs. It had struck Frisk with such a force that it stuck through the back of their ribcage. Somehow Frisk was still standing strong and defiant. 

13/20

Almost half their life was gone in one hit. Sans had seen them take worse, he’d seen them with HP as low as his own at times. But this was different. He could see Frisk trembling in fear as the spear dissolved into nothing. Frisk let out a small, frightened sob and Sans wrapped his arms tightly around them as he let his first blaster dissolve into nothing. 

“sweetheart listen it’s okay, you’re okay,” Sans said as he rocked his Frisk back and forth. They were starting to panic, their chest heaved as they struggled to suck in air they didn’t need. Sans wrapped his arms tightly around his baby. Frisk had to come first, he wasn’t going to let them die on his watch.

“um, me? You gonna-“ That was as far as the blue version of himself got before Sans’ head snapped up and he cast the trio a hateful glower. Bastards. They were just stupid, cartoonish versions of the monsters he knew. If this Sans was anything like him then he would figure him out soon if he hadn’t already. 

“don’t follow me,” Sans spat at himself before he vanished in a crackle of red magic. Back to his home, and he prayed to anyone who might be listening that this Sans had already repaired his machine and Sans would have an easy out if it came to it.


	3. Two Times Two

**Summary for the Chapter:**

> Two Sans' have a nice little chat.

**Notes for the Chapter:**

> feel kinda iffy about this one, it's mostly talking so I hope I kept it interesting enough!

Sans teleported into his room, clutching Frisk close to his chest. It wasn’t his room, it was the room of a Sans from a more peaceful life. A Sans without a child, clearly. Sans wrinkled his face in disgust and he set Frisk down gently so he could tear the pile of sheets off the bed. 

.:Dad?:. Sans saw Frisk sign out of the corner of his eye. They were starting to shake, the bones making a soft rattle and Sans bent to pick them up and hold them tightly to his ribs. He sat down on the bed and leaned back, resting his shoulders against the wall and holding his Frisk as they finally began to sob. He didn’t know how much they could remember, if their mind had been frazzled when they died and it was just Sans’ reaction to Undyne that scared them so but . . . Sans thought they could probably remember. Frisk knew it was Undyne who had killed them. 

Frisk trembled violently and wrapped their fingers around the bones of his ribs and Sans bent his head down to give Frisk’s forehead a skeleton kiss. Their mind was far gone in a place Sans couldn’t reach and all he could do was be there for them.

He knew the feeling. He didn’t know why he did, those memories had been stolen from him but the trauma from whatever he had been remained. His Papyrus had comforted him in this way once, before they learned that affection was weakness. Before his Papyrus grew to hate him and his weakness. Before Sans had to hold himself and rock while his mind turned against him and forced him to relive a past he couldn’t consciously remember. Was that what it was like for Frisk? He had been too afraid to ask. 

Tears welled in Sans’ own eye sockets and he found himself whispering, “it’s okay sweetheart. it’s okay i’m so sorry – i shouldn’t have let you get hurt i’m so sorry i-i’m, god, kiddo.” He needed to get them food, get their HP back up and run to repair the machine in the back room. He had to see if he could give his child their life back, their humanity back, their freedom to return to the surface – he didn’t care what he had to do to make it happen. He would do anything for them. 

Frisk signed something against his chest and Sans looked down, but Frisk was unwilling to push away enough for him to see what they were trying to sign. He furrowed his brow as he noticed their head was turned slightly, so they were looking at the door Sans stiffened, the little white dots of his eyes vanishing and leaving his sockets black voids as he turned his head slowly. He was at the door.

Well, this world’s version of him. Wearing a stupid blue hoodie and that mirthless grin. “woah, woah, hey now,” Sans said, holding up his hands when his counterpart held Frisk closer and snarled, “i teleported here, you’ve still got some time to do your thing before we have a chat, okay? i doubt undyne would guess you would come here. maybe? we tend to be pretty predictable, me.”

Sans bared his golden fang and spat, “fuck off, my kid is upset!” His counterpart raised his hands in a placating manner. He visibly stiffened at the mention of Sans’s kid, though, and Sans knew that would be a large part of their talk. 

“alright, i’m out of here,” Sans said as he put his hand on the door, “but first you need to tell me your name-“

“sans.”

“no, i’m sans. my universe, my name. do you want to be ‘red’ or ‘edgelord’?” Sans bristled and opened his mouth to shout when his counterpart snickered. “shall i call you daddy too?”

If Sans had skin it would have crawled. “they don’t call me ‘daddy’, it’s just dad. and . . . comic. as in comic sans. i guess.”

Sans nodded before he opened the door and slid outside of the room. Sans let his magic eye flare before he turned back to Frisk who had started rubbing their eyes furiously. “h-hey kiddo, you just ignore him. i want you to get it out, you’ll feel better.”

.:I am better:. Frisk signed, though from their face Sans didn’t really buy it. He stared at them with a tight jaw before he relented and slowly scooted off the bed, refusing to set Frisk down. They wrapped their arms around his neck and buried their skull against his shirt. 

“love you too, sweetheart.” He held them close as he followed his counterpart out of his room into a very . . . strange house. It was the same build as his house but it looked . . . wrong. There was no crack in the wall where Papyrus has thrown him and knocked out his tooth. There were no holes in the wall where Papyrus had attacked him in a fit of rage. There was no hole in the roof where Sans had lost control and set off a blaster. It actually looked cared for, like someone cleaned it regularly and recently. It smelled bad, like overcooked noodles and tomatoes, but a nice sort of bad. 

Sans refused to look at Papyrus’ door as he walked past it. 

He found Sans sitting on a lime green couch. Facing a television without actually watching the black and white tv show with a weary laugh track. Sans – no he had to be Comicsans for a while – sat down on the couch next to him. They were silent for a while, the laugh track mocked them.

“tell me about the kid,” Sans finally said. Frisk raised their head and peeked a socket at their father’s shirt. The jacket they wore made them look like a little bear cub, and Comicsans smiled fondly down at them as he rested his hand on their skull. 

“you don’t have them?”

“no. guess i haven’t met the right momster.” The laugh track, right on cue. 

“there isn’t one. there’s only me,” Comicsans said. Frisk nodded sagely. “they, uh, were the human. you met your version of them? yeah? heh, well. guess that explains where we came from – undyne stole their soul but their determination wouldn’t let them stop. they formed a weaker soul and walked out of their skin.”

“and you’re their dad because?”

“fuck you,” Comicsans snarled and Sans gave him an utterly unimpressed grin. He was tired of being questioned – his Papyrus had been furious when he found out but Comicsans knew he couldn’t explain it. He could feel it in his soul. Monsters were forged from their parent’s magic and Comicsans guessed that when he found their corpse he must have done something. It didn’t matter. “they’re the best thing in my life,” Comicsans said softly.

“okay, so,” Sans said, “why did you leave your universe?”

Frisk sat up and looked at Sans, their eye sockets studying him so intently that he felt like he may have offended them. They shifted their jaws nervously as they raised their shaking hands and started to sign. .:Please don’t be mad at Dad. It’s my fault. I didn’t have enough determination to restart. It’s my-:. their hands were trembling so much that it was getting hard to understand them, .:I’m the one who wasn’t – we didn’t have another choice! Pease don’t be mad at Dad he’s just – he wasn’t:.

“it’s okay sweetheart,” Comicsans said as he held Frisk close to his chest once more. Sans was looking a little uncomfortable at the exchange and the laugh track blared as he looked away. Comicsans sighed as he looked back at Sans, sorrow etched in the bone around his eye sockets. “look, whatever power they had was stolen when undyne took their human soul. i can only assume that asgore has it and that’s the best case scenario. we’ll go back to our own universe eventually, i guess. but for now?” Comicsans shrugged. He was too lazy to come up with such a long term plan, all he could do was meet their needs as they arose. 

The two adult skeletons sat back against the couch and sighed, watching the two fish monsters on screen making jokes about how miserable they were. They both grimaced and looked away, Sans looked to the kitchen while Comicsans gently adjusted the oversized coat on Frisk. 

“i haven’t heard you say their name,” Sans finally said. Comicsans looked confused and Sans looked impatient. “their name, sans. what’s their name?”

“oh. well, we don’t actually know. they still haven’t started talking.” Both Sans’ looked up to where their dialogue boxes would be. They couldn’t exactly make them out well but they could see their words in lowercase comic sans the same way Papyrus spoke in uppercase papyrus. ”they’re my kid so i guess they might be a lowercase too. and i like to think they’ll be sans serif too but who knows?” Frisk frowned as best they could, but it was clear they were unused to making expressions with a face made of bone. 

Skeleton names had a certain logic to them, one that Frisk had clued in on while they had still been human but now that they were a skeleton it just seemed frustrating. Their Dad only called them ‘sweetheart’ or ‘kiddo’, refusing to address them as Frisk since that just wasn’t a font. .:I can’t talk:. Frisk signed. That didn’t mean they weren’t deserving of a name.

 

Sans sighed. “well, get the baby bones something to eat, okay? i’m going to go talk to paps and undyne. dunno what they’re like in your world but i got it covered.” Comicsans growled wordlessly but Frisk looked at Sans in open fascination. It made him feel kind of uncomfortable and he hopped off the couch as the show laughed at his feelings. “uh, okay. i got my own frisk to take care of so . . . i’ll see what I can do to keep you to yourselves.” Sans shrugged before he vanished in a crack of blue magic and left his counterpart alone. 

Sans didn’t really get what exactly it was about those two that made him so uneasy, aside from the fact that they shouldn’t exist in his universe. It was like looking in a cracked mirror, himself still recognizable but distorted in a way that Sans himself could never recreate. And that reflection could never be him, either. 

Sans appeared in Undyne’s house, in the middle of a shouting match between Undyne, Papyrus, and Alphys. “hey,” Sans said as Undyne snapped her neck around and gave him a dead-eyed shark’s glower. She looked angry, and maybe a little betrayed. Sans couldn’t explain fully how her expression made him feel. Papyrus looked up to, loving but confused and Alphys peeked out from around him, pattering her yellow claws nervously and looking more suspicious than anyone else.

Sans sighed. Oh boy, he really didn’t want to explain the truth. “so, uh, surprise! guess we better get this talk out of the way.”


	4. Fresh Fried Fish (Undyne Part I)

**Summary for the Chapter:**

> -enthusiastic chanting- UNDYNE UNDYNE UNDYNE

Papyrus accepted the fact that there were two of him rather easily. He seems shockingly unsurprised about the multiple versions of reality that different versions of Sans are able to navigate – though Sans explains plainly that he, himself, cannot do what the other him did. Though he neglected to mention that it would just take a little more tinkering of his machine to get the red-eyed Sans’ ability. Papyrus is even more enthused about the fact that a version of Sans had a child! He seemed convinced that his Sans was in the process of making a child of his own and Sans was delighted to keep chattering away about how much that won’t be happening while Undyne tapped her foot impatiently. 

The brothers could easily have talked about their alternate selves for the rest of time were it not for Undyne getting more and more agitated. Sans pretended not to notice until she suplexed a rock twice his size and lets out a scream from the depths of her SOUL that made him rock back onto his heels.

“NNNGGGHHHHH! ENOUGH!” She shouted, “Stop running away from the topic at hand!” Undyne pointed so viciously at Sans that she almost knocked over Papyrus with her arm. “YOU! What was that!?”

“uh,” Sans said, “i already said there are a quantumly undefinable number of realities-“

“Not that!” Undyne said, and Sans could feel her frustration burning over him in waves. “I don’t care about that stupid punk version of you! I want to know what you did! I’ve seen you, Sans, I know what you are. You’re not capable of that!” Undyne gestured wildly at the great scorch marks left by the blasters. “HOW did you do that? Since WHEN could you do that!?”

Sans shrugged. “dunno. i needed to do it so i did it. that’s sorta irrelevant now, isn’t it?” Undyne hissed furiously, clearly even more agitated with his lazy behavior now that she had had a glimpse of how strong he actually was. Sans shifted uncomfortably, trying to distract himself from the water soaking his pink slippers and the feel of Papyrus’ eyesockets boring into his skull. Time to make something up. “look, i really don’t get it either. i didn’t think i was capable of anything like that, honestly. when i saw a blaster aimed at you and pap, i guess i just reacted.” 

That seemed to work for Undyne, she had always seemed to think that anyone was capable of great strength if they were protecting someone. She actually looked thoughtful for a moment before she bent her knees and threw up an arm dramatically. “Sans, just imagine what you could do with a little extra training! You should come with Papyrus to my place one day!” She pumped her fists enthusiastically and Papyrus bounced around her with an enthusiasm usually only seen in Lesser Dog. 

“THAT WOULD BE MOST EXCELLENT, MY BROTHER AND MY BEST FRIEND! ALL BOTH OF US, TOGETHER!”

“oh, good, great, yaaaaay,” Sans grumbled as Undyne hooted. He was stronger than just about anyone else, even after more years than he cared to count spent doing anything but training. He wouldn’t participate but he would indulge them, and he talked along amiably with each of Undyne and Papyrus ideas as they slowly made their way to Undyne’s house. 

It wasn’t until they were at the jaw-shaped door that Papyrus stopped dead in his tracks, eyesockets wide open in surprise. Undyne and Sans both bumped into him from behind and Undyne grabbed Sans by the hood of his jacket before he could fall (and have a nap on her front lawn). “Hey punk! What’s the deal!?” Undyne protested as Papyrus began to frantically search through his bone-tight clothes for his phone. 

His face lit up when he saw the number and he flipped it open. “HELLO HU-FRIEND! SO GOOD TO HEAR FROM YOU AGAIN MY VERY GOOD FRIEND OF UNKNOWN ORIGINS!” Sans snickered into his hand, picking up on who he was talking to immediately. “YOU WANT TO HANG OUT AGAIN? AH, GOOD! I WILL, UH, MEET YOU OVER BY THE, UM,” Papyrus glanced at Undyne, “THE PLACE! GOODBYE!” It was hard to say who the goodbye was meant for, since Papyrus flicked his phone shut and blazed past his friend and brother, cackling all the way. 

“We had a cooking lesson,” Undyne grumbled irritably.

“he’ll probably be back,” Sans said. He stuck his hands in his pockets and blinked sleepily. “well,” he yawned, “i’m beat. gonna just go home for a nice forever nap.” He grinned pleasantly but before he could vanish into thin air Undyne grabbed him by his elbow.

“Wait!” Sans paused and blinked at her in confusion. The grab wasn’t nearly as aggressive as her usual gestures but she also seemed somehow meek. How . . . creepy. “Look, Sans, I know I took it a little far with that ‘other you’.”

“just call him comicsans.”

“I’d never arrest you – or the other you even if he is a punk. And, um, sorry I upset your kid?” Oh. That’s why she looked so uncomfortable. 

Sans coughed nervously and rubbed the side of his skull. “geeze, you and papyrus both are so chatty about that baby bones. look, undyne, i’m sure that you didn’t do anything wrong, comicsans kinda seems like he’s always that angry. but, uh, for the record i still don’t have a kid.” Undyne looked incredibly uncomfortable and Sans knew the feeling. “you could probably just talk to that sans about it if it really bothers you that much, i get the feeling that the baby bones has a forgiving personality.” They were still Frisk, weren’t they?

Sans smiled nervously and shrugged as his hands went back into his pockets. “Okay, yeah. I get it. But Sans, you know you never actually said where the other one was-“ Undyne went to make eye contact and found that Sans has already vanished. Figures. Undyne hissed in agitation before she stormed into her own home, disappointed that she wasn’t accompanied by at least one skeleton. Well, with any luck Papyrus would remember his cooking lesson and she could have some company.

Four hours later she walked into Snowdin with charcoal and ash smeared on her fins and a new name punched in her contact information.


	5. Drowned A Fish In Tears (Undyne Part II)

**Summary for the Chapter:**

> this chapter covers Frisk's death in underfell and basically takes place pre previous chapters. I don't think it's too bad but it is still a child getting murdered and there's some mentions of previous abuse so consider this your warning.

**Notes for the Chapter:**

> I like the idea of underfell Undyne hating fighting but having to do it anyway. Like, Ut Undyne is a warrior because she wants to save everyone but uf Undyne would have given up hope and just fight because she doesn't think she has another choice.

Frisk ran along the pier, throwing themselves across boards of wood in desperate attempts to avoid the blue gleam of magic spears shooting up from under them. They had stopped trusting their own ability a long time ago, and where instead blindly obeying the flower clinging to their shoulders. 

“LEFT!” Asriel screeched, “nonono, RIGHT, BACKLEFTBACKRIGHTLEFTLEFT! S T O P!” Frisk leaned back as they had been about to spring forward and a spear grazed their shirt, tearing a long line up the front of it before it stabbed them hard in the chin. Frisk isn’t sure if they threw themselves back or if Asriel dragged them back but next thing they know they’re on their side on the pier and all around them the wood is glowing blue. 

“Don’t move,” Asriel instructed weakly as Frisk closed their eyes and hugged him close. They expect to be torn into shreds, they expect to wake up touching their save point in Waterfall as if their soul hadn’t just been ripped into thousands of pieces. But . . . nothing happened. Frisk could see light through their eyelids and hear the faint hum of magic as it remained static. 

Very slowly they opened their eyes and they were greeted by a wall of blue. Frisk turned their head and saw that the blue surrounded them on all sides, forming a large circle that Frisk was able to stand up in. Very slowly they got to their feet and looked around. They could see a little between the spears but they glowed so brilliantly that everything beyond was solid black. 

The spears were unmoving. They stayed up around them, locking them in place and Frisk was certain that if they moved forward and touched one their soul really would be turned green. .:Do you see her?:. Frisk signed after a long pause. Asriel’s roots twisted on their shoulders as he tried to get a better angle.

“I don’t see her under us but-“ he was cut off when a spear split the air beside Frisk’s neck and impaled his anther, right between his eyes. Frisk screamed wordlessly and turned to grab him as he was torn from their shoulders but he was thrown past the wall of spears.  
Despite knowing what would happen, Frisk threw their hand forward and there was an immediate blast of pain through their fingers. Frisk drew back with a hiss, clutching their hand to their chest and squeezing the torn bits of their shirt around their newly mangled hand. Tears stung at their eyes but without their hands they couldn’t call for help!

“It’s okay,” came a low voice, soothing and mournful. Frisk turned slowly, shaking as the spears before them faded and they were faced with Undyne. She wasn’t wearing her armor, but her casual clothing made Frisk more nervous and they backed up. “Alphys wants him back so – so I won’t hurt him.”

Frisk pulled their hands out of their shirt and did their best to sign, .:I won’t let you hurt him!:. Undyne looked sad. Her lips part slightly over her crooked fangs and her one good eye scrunches up a little. There’s an emotion on her face that Frisk hasn’t seen much. It’s the look Asriel had when Toriel told them never to come back. It’s the look they saw on Sans’ face after Papyrus said his brother was a weakness. It was as though they thought there was something so utterly tragic that Frisk wasn’t able to understand. 

“Kid,” Undyne said and there was a funny hitch in her voice, “I . . . I don’t want to do this. Please understand that-“ She cut herself off but she chewed on her lip. “No, I guess how I feel doesn’t really matter. But I swear, this will be as painless for you as possible.” She pulled out a jar from the bag on her hip and Frisk felt something in their stomach twist. 

Frisk held their bad hand to their chest and shifted on their ballet shoes so they were on point. They were glad they didn’t have a weapon that needed to be held. 

But the battle did not start. 

The world did not turn black, no menu appeared. 

Undyne hung her head and for a moment and a glimmering tear fell. 

Frisk shifted back to standing on flat and they nervously shifted forward. Undyne was struggling, Frisk smiled weakly and reached out their good hand to touch her arm. 

As soon as their arm was fully extended a spear rammed up through their elbow and pierced their skin on the other side. Frisk tried to reel back but all they managed to do was tear their flesh like old cloth and they let out a scream of agony. It hurt! It hurt so much worse than having their soul shattered!

The spear vanished and Frisk collapsed. They whimpered and grabbed at their arm with their shredded fingers, tears streaming down their face. Their hands were useless now, they couldn’t beg for help anymore! Undyne stepped into the circle of the spears and it closed behind her, trapping them together. From the ground, Frisk could see Undyne’s face. They could see the sorrow and pity there and Frisk wondered if they were supposed to feel bad for her.

“I. . .” Undyne said softly, “please understand this is the only way.”

“This is the only way brats learn,” their much older cousin sneered as she stood over Frisk. Her lips were pulled back over her pearly white teeth. Frisk tried to sign that they didn’t mean to do anything, they didn’t know what they did! “STOP IT! JUST TALK!” Their cousin screamed. She had pulled off her belt the way her dad did, the way Frisk’s uncle did. 

Frisk screamed and threw themselves back, sitting up and kicking their body away from their cousin and shoved their back into the wall of spears. They had to get away, they had to run! The only way to get away was to start running but there was no way to run? No, they had been outside in the park! But . . . They were in a cage? Frisk’s mind ran at a million miles a minute, frantically grasping for fractured memories and their warped reality as pain made them delirious. The feel of the magic spears burned the clothes and flesh on their back, tearing down to the muscle in fat strips. 

Their cousin was sobbing, but Frisk didn’t know why. There was a feel of a belt across their face, the metal stinging their cheek. Frisk tried to kick further away from Undyne as she stepped through the illusion of Frisk’s cousin and into the memory of their uncle standing over them with his face twisted in rage. Frisk shrank away and let out a horrified, shuddering breath as a distant call from Asriel snapped them back into their body. They pulled their back out from the spears but they just wound up at Undyne’s feet. 

Why was she crying!? She was doing this to Frisk, She had done this to Frisk! Or, no were those different people? Frisk couldn’t separate them as a spear rammed through their left thigh and anchored them to the pier. Another spear went through their calf going a different direction, pinning down their other leg. A spear through their left wrist, a spear through their right hand. Frisk thrashed and screeched, their mind reaching frantically for the few in their life who had shown them genuine kindness.

Asriel! Please help!

But he didn’t come. 

The spears pulled Frisk’s body down, forcing them to lie on their back.

Mama! Please help!

Undyne’s hands were on their end of the container and she twisted each side of it. There was a hiss of air as it opened. 

But she didn’t come. 

Why was Frisk still alive? They had only ever died from their soul shattering before but surly their body couldn’t take much more of this! How was . . .? Frisk noticed that Undyne’s hand was covered in a swirl of green magic and it occurred to them that she must have been healing them just enough to keep them alive. Healing just enough so that each stab of agony wasn’t weakened by the pain that came before it. 

SOMEONE! ANYONE! HELP!

Finally, Undyne summoned Frisks soul to battle. Frisk saw black creeping into their vision, swirling thick and black but if it was a battle or death Frisk didn’t know. Their soul formed over their chest, glowing and warm and Frisk closed their eyes, letting their consciousness slide from their body into their-

Undyne caught their soul in the jar like a firefly. 

BUT NOBODY CAME

As soon as the little chamber closed Frisk went still but they did not die. “Sorry,” Undyne said faintly. Her spears faded, but the human’s body did not move. She slipped the jar back into her bag before she knelt and pressed her green hand into Frisk’s chest, healing their body until their torn clothes and the bloodstain on the pier was all that remained. Undyne stood and looked down. There was nothing left in the human, but they were still alive. The way their eyes were trained on her purse, Undyne had to hope that humans had it in them to live without their souls. 

“I’m sorry,” Undyne whispered. Not that it mattered. It didn’t even make her feel better this time. Undyne wiped the tears from her eyes before she looked up, her face set in stone as she looked for the flower Alphys had ordered her to retrieve. But . . . it was gone. The flower was gone! Undyne was actually stunned. It had abandoned the human? Undyne could have laughed. After the human had begged for the weed’s life it went and left them. 

S A N S !

“I’ll find it later.” Undyne muttered. 

S O M E B O D Y C A M E

Undyne turned to run down the rest of the pier but she stopped dead in her tracks as a short, squat skeleton in an oversized jacket stood before her. One eye burned an inferno of swirling, hateful red and it struck Undyne how well he could rip open her throat with those fangs. She glared down at him. “What do you think you’re doing?” she asked coldly.

Sans said nothing. Undyne’s skin crawled. 

“Alright. Fine,” Undyne said stiffly. She brushed past him but before she could get all the way away his hand shot out and he grabbed her wrist. 

“what the fuck did you do to them?” Sans asked. His eyes were on the human body sprawled over the pier like some sick modern art display. 

“What, you want to run to Papyrus so he can take credit for it? Piss off, shorty.” Undyne tried to pull away but Sans yanked her roughly. Undyne curled her lip and formed a spear. She made to bring it down on his head but a red bone met her attack and stopped it. Sans hadn’t looked away from the human during the whole spat. There was no way . . . “You . . . actually care?” Sans said nothing. Shame burned in Undyne’s SOUL. “Asgore has absorbed the other souls. If I didn’t then he would have killed me. Killed Alphys.”

“you deserved it more than them.” Sans said. It was impressive how much hate he could pack into such a soft tone and Undyne almost flinched away from him. She couldn’t respond to that one. He was right, she supposed. She was a grown woman who had lost all her will, nothing mattered to her anymore outside of the love of her life. She wasn’t worth the life of a child so full of love. 

Sans let her go and Undyne walked past without another word. She didn’t think she could handle seeing what would happen next. If Sans was going to mourn, Undyne might actually crumble to dust then and there.


	6. Oh Daddy Dearest

**Summary for the Chapter:**

> Frisk learns something new!

Frisk’s eyes snapped open when they heard the loud, booming voice of Undyne. They were in a dark room, inky black and so very cold. They couldn’t move their arms very well, they had been tucked in too well, bundled into a thick blanket and covered in a heavier coat. A pillow was tucked neatly under their head and behind their back and the bed was made so neatly for their father’s usual style. They would have been impossibly comfortable wrapped in bed had it not been for the shouts of their murderer and the sharp voice of Papyrus. 

“hey,” a voice rasped but before Frisk was able to calm down they ripped themselves out of bed to leap out of bed, and the top of their skull met something hard. Frisk yelped and fell to the ground as a heavier body flopped over beside them. 

“you two are really graceful,” frisk’s dad said, but his voice sounded distant and far too clear. The lights flicked on and the dots of light in Frisk’s sockets went out. Their actual dad, in red with a gold fang glittering sat right beside them, rubbing his jaw where Frisk had headbutted him and glaring with spite and loathing at the door. “look, i’m not here to bother you. heck, i didn’t even tell them you were here. but, uh, if you want to come downstairs papyrus has made dinner. and there’s a show on tv i think you might like.” The blue Sans winked at Frisk and they tilted their head at him, the little lights in their sockets tentatively appearing to study him.

He wasn’t their dad, he seemed so fundamentally different but Frisk still felt a desire to trust him. They turned slightly before they got to their feet, using the bed and their dad to help them get up. .:Blue-Sans?:. Frisk signed, .:I heard Undyne.:.

Sans nodded, “well yeah, she’s here.”

“w h a t”

“hey don’t take that tone with me, me. i can do it too.” Sans looked annoyed and he folded his arms before he leaned into the doorframe. It dawned on Frisk that their dad and Sans might not get along. Still, when Sans looked back at them he seemed to put in an effort to make his face look less tense. “look baby bones,” he was going his best to sound gentle and Frisk grabbed their dad’s hand as he got to his feet. “i get it, you know. i’ve had to interact with someone who killed me like nothing was wrong so i get it.” He looked so sad and Frisk tilted their head.  
Sans bent his knees so he was eyelevel with Frisk, “but this version of her isn’t like the one who . . . the one who hurt you. she’s here because she made friends with our version of you and set her house on fire. i don’t actually know how that happened. but, you know, if you guys want to join us then that’s good. paps is really happy that he’s got a niecphew.” 

Then he was gone and their dad groaned like an old dog. “he’s a fucking prick. how the fuck is a guy like that me?” Frisk turned to look at their sullen dad in surprise. They were different, sure, but Frisk could still recognize them as maybe, once, having the potential to be the same person. They put their hand over their jaw and giggled.

“oh?” The dad asked. He grinned widely as his gold tooth flashed and his red eye flickered. With a flick of his wrist Frisk was back on Sans’ bed and he started tucking them in again. “are you saying somthin’ about me? oooh, you gonna act like a tough guy now?” he tickled their ribs and Frisk shrieked and started to squirm furiously. “looks like you are my kid! i’m proud kiddo, keep that up and you’ll get your own gold tooth soon.” 

.:No! I don’t want to sleep!:. Frisk managed to sign even as they flailed and laughed helplessly. Sans snorted in amusement too but he shook his head.

“you’re barely awake, sweetie. you gotta sleep.” He went back to tucking them in again but Frisk kept squirming free. 

.:You need sleep too!:. they protested. Sans always left their hands free, even as he tried to restrain them in a sea of blankets. .:but, I was thinking.:. they smiled nervously, and they felt their eyes gleam a little brighter. Sans paused finally and looked a little put off by their uneasy expression. Frisk was so unused to having a bare skull that their emotions were always plainly visible – at least to other skeletons – and their dad could read what Frisk was feeling like an open book. 

.:Maybe blue-you is right? Maybe we should go downstairs.:.

“wha-wait, no! sweetie, no you don’t have to do that!”

.:I know I don’t have to,:. Frisk signed, .:but I think that I want to. He’s right, this is a different Undyne and, well, plenty of people have killed me before. I can’t hold that against her.:.

“yes you can,” Sans grumbled. He certainly did. Frisk smiled sadly and shook their head. 

.:I want to believe that everyone is good. I want to give her a chance.:.

Sans was silent for a long moment, just studying them. He seemed not entirely thrilled with their plan but after a while he sighed and picked up his jacket, offering it to them. “sweetheart, you’re a good kid. you’re better than any of us deserve, here or in our own world.” Sans gave Frisk’s forehead a skeleton kiss with his teeth. When he sat back he looked like he was contemplating something before he shrugged and said, “if you get at all uncomfortable or uneasy around her i’ll get you out of there. i won’t even kill her if that would make you feel better.” 

Frisk finished tugging on their coat and Sans picked them up, holding them so they could wrap their arms around their neck as he tucked a neat arm under their legs. “i’m proud of y-“

Frisk opened their eyes and were met with only darkness. They were confused but it seemed that they were lying on their side again, under blankets and surrounded by pillows. Their dad was sleeping on his face on the treadmill in the center of the room, his snores slightly muffled by the unused machine. A faint red light began to glow from Frisk’s eye sockets as they at first wondered if Sans had somehow really tucked them back in. 

Frisk shimmied a little as they tried to sit up when suddenly, “YEAH, GO PAP! SHOW THAT PASTA WHO’S BOSS!” The scream that had awakened Frisk to begin with. 

“shit!” Frisk heard their dad hiss as he woke up, and he was over them in a second, his own eye glowing brightly with concern. Ah, that was why they had headbutted him the first time. This time they remained still and their head remained unhurt as small red tears began to form at the corners of their sockets. A faint red glow started in the depths of their skull, pulsing weakly but strong enough to clearly illuminate their hands in the dark.  
“sweetie?” Sans asked, looking horrified. The last time he had seen them cry was when they had woken up from death, and he had never seen their eyes manage any sort of glow.

Frisk freed their hands from the blanket and slowly told their father, .:this Frisk just reset but I can still remember everything.:. Sans blinked before he picked them up and tucked their skull under his. Sans knew what they meant.

“i’m sorry,” he said, “fuck, kiddo, i’m so sorry.” Frisk wrapped their arms around their dad’s neck and squeezed him tight. Their tears dripped onto the shoulder of his shirt, leaving faint hints of glowing red before the lights flicked on and they turned to normal dark spots of water.

Frisk didn’t move at all as they felt their Sans look up and glower at the Sans they already knew was at the door. “yeesh, didn’t think you guys would be having a touching family moment in my bedroom. don’t suppose i can talk you into renting a room at Bonnie’s sister’s hotel?”

“i’ll ram your femur through your fucking eye socket if you aren’t careful,” Their dad warned. 

“no you won’t.” Sans cocked his head, and when Frisk peeked up they noticed there was a predatory edge to his grin before it morphed into shock when he noticed their tears. Or the faint glow of red magic still shining out from the depths of their skull. Frisk wasn’t sure which would be more surprising. “um, okay,” Sans said before he looked back at their dad, “look, i’m not here to bother you. heck, i didn’t even tell them you were here. but, uh, if you want to come downstairs papyrus has made dinner. and there’s a show on tv i think you might like.” 

. . . The same words. Frisk felt their father bristle like a hostile wolf. 

Frisk didn’t really want to play out the same conversation again, not after they already reached their own conclusion. Frisk pushed away from their father and scooted back in their seat. Their dad let them go, knowing that Frisk wanted to sign.  
.:I know Undyne’s downstairs already. And I know that she’s not the one that killed me.:. Frisk felt their dad grow rigid but he didn’t interrupt. .:I think that I’d like to try meeting her.:.

“really?” both Sans’ asked with various degrees of shock as Frisk wriggled into their father’s jacket.

Frisk looked at the blue Sans at the door and made a grabby motion of one of their skeleton hands. He looked a bit confused but approached warily, getting as close as he was willing to their dad. Frisk could have laughed. As different as they were, he was still their father. Frisk felt a desire to trust him, as deeply rooted as their fear of Undyne. With a little giggle Frisk hopped off the bed and grabbed Sans’ hand with one of theirs. They tugged him along as they reached out to grab their dad’s hand too.

“um,” their dad said, “seriously? i can carry you down if you want. you don’t need to hold his hand.” Frisk shook their head before they forced their permanent-grin into a wider one. They swung their hands between the two of them before they strode for the door, not allowing either of them a chance to escape.


	7. Pasta and Pie

Undyne and Papyrus were screaming as their Sanses walked them out of his room. Frisk wondered if they decided to lift up their legs if they would just continue to carry them along, swinging them the way Frisk could remember seeing human parents doing with their children above ground. Frisk tightened their grip on their dad’s hand and they leaned in a little closer to their actual father, though even they weren’t sure if it was because of how safe he made them feel or if it was because they didn’t want him starting a fight when there didn’t need to be one. 

“OH! HELLO BROTHERS! AND BABY BONES!” Papyrus said, sticking his head out of the kitchen as each Sans put a fuzzy pink slipper on the first squeaky step. They were squeezed in a bit too tightly together but Frisk refused to let them do anything but walk elbow to elbow. 

“hey bro.” Frisk peeked around their dad and smiled nervously at the friendly looking version of their uncle. Their smile vanished as Undyne stuck her head out of the kitchen as well with a huge, toothy grin on her face.

No, no. They had to remember. This woman hadn’t ripped out their soul. This woman had befriended her version of them. Frisk . . . Frisk had to make themselves give her a chance. 

Even so, Frisk flinched back behind their dad when she greeted them rather aggressively. “Paps and I made a biiiiiig pot of pasta! You better be hungry, punk!”

“since when can the boss cook?” their Dad muttered so softly only Frisk could hear. 

“AND THERE IS THAT SWEET QUICHE THAT SANS MADE YESTERDAY!” Papyrus said, “SWEETS ARE GOOD FOR BABY BONES, EVEN IF THEY ARE DISGUSTING!”

“it’s a pie.”  
“since when the fuck can i cook!?”  
both Sans grumbled in unison as they plopped Frisk onto the couch and sat down on either side of them. Frisk only let go of their hands for the briefest of moments so they could switch sides and Blue-Sans handed them the remote to the tv. 

Not that they did anything with it. Blue-Sans had been right, they were very interested in the show already on as it panned over to them. Frisk. A human, living Frisk. Dressed in the same bright clothing they had fallen in, before their dad had found something more suitable for their world. They were facing off against a square robot in the middle of asking them a question about something called Mew Mew before the short, plump little yellow monster behind it suddenly blurted out the answer. 

Frisk cocked their head. Was this a game show? It seemed like the undergrounds version of one and Frisk couldn’t help but giggle as the robot turned and gave the yellow creature a withering glower. Frisk had never gotten to their version of whatever this was and Frisk couldn’t help but enjoy the surreal antics. This didn’t seem so scary, it actually seemed fun! 

“Well, guess we’re sitting on the floor,” Undyne said as she walked out of the kitchen with five bowls balanced carelessly on her arms. “Ugh, is that Mettaton? Do we have to watch that jerk?” Undyne suddenly hissed when she noticed what was on the television. 

“THAT IS FINE, I KEEP OUR FLOOR WELL POLISHED” Papyrus said. Frisk smiled tentatively at him, happy he seemed so much happier than their actual uncle and optimistic that this wasn’t an act. Undyne shoved sloppily assembled bowls of noodles into everyone’s laps before she sat down with her’s and Papyrus’. 

“oh. guess the boss still can’t cook,” Sans grumbled as he picked at the overcooked noodles and undercooked sauce with his free hand. He wasn’t wrong, it was far from the best looking dish Frisk had ever seen but they had also eaten an abandoned quiche off the muddy ground and this had been made with love. Asriel had said that was why his mum’s snail pies were so good. 

Slowly, Frisk eased their hands out of their dad’s as the television blared, “WHO DOES DOCTOR ALPHYS HAVE A CRUSH ON?”

Alphys? Frisk thought they could remember that name. They frowned thoughtfully as their twirled their fork around the noodles. They knew they had heard that name before, even if they had never met a little yellow monster. Someone must have said her name before. Frisk glanced up just as their counterpart put their hand down on the name ‘Undyne’. The only one who seemed completely unsurprised was their dad, who seemed to be radiating ‘well, duh’. 

“WOWIE!” Papyrus said. Frisk looked down at Undyne, who was sitting with her back to the couch and a brilliant purple blush on her scales. 

“Oh my god,” she said faintly. Dead silence fell as the robot on the television rambled on before Undyne leapt to her feet, sending her bowl of pasta flying across the floor as she stood with her fists clenched and her head turned up. “OH MY GOD!” She bellowed from the very depths of her lungs before she grabbed the couch with three skeletons still sitting on it and hoisted it over her head. “OH MY GOOOOODDDDDD!!!” Undyne yelled so loudly Frisk thought the windows rattled. 

They flung their arms around their father, and buried their face in his shirt, letting their own bowl of pasta splatter across the floor and knocking their dad’s free as well. It was instinct spurred by the unexpected aggression and their dad wrapped his arms around them immediately. “SHE LIKES ME,” Undyne screeched. 

“says mettaton,” said Sans as Undyne slammed the couch back down.

“She likes ME! O H M Y F U C K I N G G O D!”

“don’t fuckin’ curse in front of my kid!” their dad spat as he held Frisk a little closer. But his words fell on deaf ears. Undyne had scooped up blue Sans and twirled him around before she carelessly left him on the table and pulled up Papyrus. 

“THIS IS WONDERFUL NEWS, UNDYNE! ALTHOUGH, I THOUGHT YOU KNEW THAT SHE WAS FOND OF YOU?” Papyrus said as Undyne almost lifted him off his feet as she spun him. 

“I didn’t - but have to! Oh, I should go visit her no- no that’s too obvious. I should write her a love letter! Yeah! Alphy is smart, I need to use words in a letter so I don’t mess up! Shit, I don’t know what to say. Hey Papyrus so you know how to seduce lizards?”

“NOT REALLY, NO.”

“Okay, well you can help me come up with ideas. And SANS!”

“yeah?” Blue Sans asked but Undyne waved him off. He looked a little miffed.

“Not you! You have worse luck with women than Papyrus! I mean RED SANS!” She turned on their father, and when Frisk peeked up they saw a passionate fire blazing in her eyes. “You have a kid! You gotta know how to seduce monsters!”

“uh, i mean i, um,” their dad said meekly. When they looked up from his shirt they were surprised to see that his sockets were empty and he had a dark blush of red magic. “i’m sorta their, y’know. their only parent?”

“What, that’s how skeleton’s reproduce?” All skeletons present shrugged. “That’s AWESOME! But besides the point. Sans, Paps! C’mon!” Undyne grabbed her versions of Sans and Papyrus and bodily hauled them up the stairs, hooting about love letters and Alphys as she hauled them into Papyrus’ room. When the door slammed shut behind them silence fell like a thick blanket over the living room.

They sat on the couch in silence for a few moments both trying to figure out what had just happened before Frisk ducked their head and giggled. How strange! Frisk was actually delighted by these versions of everyone, even if their father looked baffled. 

The television had turned to snow, and there was a faint hum of static. Frisk must have left the studio since this was around where they had reset the last time Frisk had to hope that they had found a save point. They didn’t really want to relive that again, and they slid out of their father’s arms to start picking up the bowls that had been thrown across the room. It was habit, a desire to neaten up the mess they had helped make before Frisk got in trouble. But, to their surprise, two hands scooped them up from under their armpits and Frisk was lifted off the ground. 

“don’t you fuckin’ dare clean up after those idiots. it’s chow time for baby bones,” their dad said, and he was unmoving as they squirmed and protested against being carried into the kitchen. They were set neatly on the counter, next to a mighty column that appeared to hold the sink. Sans grumbled as he started rummaging through the fridge before he made a small ‘ah-ha!’.  
“so this is what the boss was talkin’ about.”

Frisk sat up and peered over, spotting the untouched pie balanced carelessly in one of their father’s hands. He grabbed a spoon and stuck it in before he handed the whole pie to Frisk, seemingly oblivious to how their eyes lit up and their heart swelled. The crust seemed a little overly browned and flakey, and the filling seemed to be the same consistency as the pumpkin pies Frisk had seen above ground. It didn’t smell just right, though. There was a faint smell of butterscotch overwhelmed by vanilla and cinnamon, and when Frisk took a bite they found it to be strangely gritty. It wasn’t bad, but it seemed as though the hands that had made it did so out of boredom – the eggs hadn’t been separate even if there were no shells, the butter had been heated nearly to boiling instead of being mixed in at room temperature, there was just a tad too much sugar that had spilled onto the bottom of the pan, making a patch of crust caramelized and impossible to scrape off the metal. 

It was the best thing Frisk had ever eaten. Sans had made this! It wasn’t as good as the food THEIR dad had made for THEM, prepped with Frisk specifically in mind but it was still so good that Frisk could have cried. Frisk happily spooned pie into their mouth, doing their best to chew without a solid plain of their lower jaw. It was still hard to chow down without a tongue, cheeks, gums, muscles . . . but even if Frisk managed to spill pie onto their lap they couldn’t be stopped. 

Frisk swung their legs against the counter and hummed pleasantly as Sans stormed around, ranting furiously about something and rattling the bones in his arms ever time as he tried to make a sharp point.

**Notes for the Chapter:**

> I've noticed that a lot of people think that when Paps comments on Sans' cooking abilities that it means that he's actually a bad cook. I just assumed that he was actually really good at baking but Paps hates sugar.
> 
> Also, he was probably complaining to Toriel that Paps hates his cooking and Tori mentioned Cinnabscotch pie is the cure to any bitter heart and Sans did his best. Probably better than Asgore's attempts but nothing beats goat mama's baked treats. ;;A;;


	8. Into the Fryingpan

**Summary for the Chapter:**

> Frisk wants to befriend UT Undyne.

Frisk had a decent night, all things considered. Every time this Frisk reset they jerked awake but it only seemed to happen twice before Frisk seemed to find a place to rest and the young skeleton was able to peacefully snuggle up. For the first time in a long time they were actually able to sleep in late, only waking up at what must have been noon. It was hard to tell without a sun but from the noise outside the house it was safe to say that the monsters of Snowdin were largely out and about. 

Slowly, Frisk peeled the blanket off their face and looked around the room. It was still dark, but they found that when they let the little balls of light get as large as possible they could actually see through the room easily. Well enough to see that their Dad wasn’t there. 

Frisk sat up and looked around, confused. Sans had only let them out of his sight for the briefest of seconds since they had died – and that had only been when they left their own universe when they had to go one at a time. Since Frisk had immediately run into Undyne and Papyrus Frisk had been prepared for him to keep them attached at the hip but it seemed that he had let them be. Frisk hoped that it was because he thought that the people around them were safe and Frisk could take care of themselves, and not because he had been dusted himself. 

Well, if he had been dusted without Frisk noticing then they supposed they would be dusted themselves before they had a chance to know what was happening. 

Frisk slid out of bed and started to look around the room. Their dark clothes felt heavy against their bones, and Frisk could feel the Waterfall mud still on their shorts. Their dad was a little taller and broader than Frisk themselves but his jacket was perfect, even if the sleeves when past their fingers and it came down to their knees. This Sans was the same size, wasn’t he? That was good.

The most random of things in the room seemed to be locked in Sans’ room, like he had just gone through and locked every third drawer before he gave up halfway through and just went to sleep. Frisk was tempted to try to form something with their magic and get in but they reminded themselves that this wasn’t their dad, and they didn’t know what he might do to them. Not only that, but Frisk didn’t know the ‘plot’ of this universe, and they were aware they might ruin something by thoughtless meddling.

In the end, Frisk found a small stash of clean, moth-eaten clothing crammed in the absolute back of Sans’ dresser. They must have been given to Sans by his Papyrus (he seemed to like strange clothing) and Frisk giggled as they pulled them out and changed, leaving their own dirty clothing folded neatly on the top of the bed.   
What they had selected was a button down shirt the color of an orange creamsicle with happy little patterns of pineapples and pink flowers. One of the buttons was missing and Frisk accidentally skipped one loop somewhere so it hung off them unevenly. To hide this, Frisk decided to tuck it neatly into the shorts they had found – a pair that would have been uncomfortably short on Sans but were almost knee length on them. They were striped vertically with a pleasant pastel rainbow and Frisk found a braided twine belt to synch it to their hip bones. Before they left, Frisk donned their Father’s coat once more, snuggling comfortably into the thick fabric. 

Frisk had never really been allowed to wear whatever they wanted aboveground and they loved each item individually. Though, they still would have to ask this Sans about using the wash so they could wear their own clothes. As nice as it was to dress themselves, Frisk felt strange wearing someone else’s clothing.

As softly as possible, Frisk slipped out of the room and into the hallway. The plush purple and orange carpet felt wonderful under their bare feet and Frisk wiggled their toes with each gentle step. They walked to the railing and used it to lift themselves up, the only way they could see the living room without actually going downstairs. 

Their dad wasn’t there, and Frisk felt the first pang of worry. The house itself seemed small and quiet, no other skeletons were visible. There was no noise from the kitchen and without any lamps on the only light was provided by the gentle light of the muted television, casting light on the sleeping Undyne on the couch. 

They couldn’t smell any dust. They knew that smell all too well, like burnt rubber and dead coals. Of course not, this Undyne was a good person. Their dad would never have left them alone with her in the house if she wasn’t. 

Wordlessly, Frisk slipped down the stairs and tiptoed past the TV as they made their way into the kitchen to retrieve the pie from the fridge. The night before Frisk had eaten the center of it, only the filling and leaving the crust scrapped clean. It wasn’t like they needed to eat healthy anymore – monster food dissolved into magic as soon as it was swallowed and was absorbed completely. There wasn’t a single good reason not to only eat what Frisk loved!  
They found a serving spoon and started scraping out the rest of the filling on the walls of the pie, still eating very carefully so no food fell through them. If they had managed not to spill the night before then they certainly wouldn’t drop any food on their clean clothing!

Frisk got halfway through before they looked down with a frown. It seemed very greedy. They saw the fridge, it was loaded up with pasta and condiments – and not even any mustard like their dad liked! After a pause and some nervous shuffling Frisk left their serving spoon on the counter since they couldn’t reach the sink, and they fished out a couple forks before they padded into the living room. 

Undyne hadn’t moved an inch.

Slowly, Frisk inched forward, taking about ten minutes before they were at the edge of the couch. Undyne was turned away, her eyes squeezed shut and looking oddly tensed. Did she really sleep like that? Maybe she was always grumpy because her neck hurt.   
Frisk reached out their hand and tapped her shoulder gently. Immediately, Undyne let out an exaggerated yawn. She sat bolt upright and stretched. “Oh woah! I can’t believe I slept in this late!” She declared, not sounding tired at all. Frisk blinked and cocked their head. “Thanks for waking me u-“ Undyne looked over at them and stopped dead. “oh my god?” She muttered, “you really are his kid.” Frisk looked down at themselves, oblivious to Undyne’s dislike for their lothing. Was there something wrong with the pie? 

“Uh, what’s up punk!?” Undyne abruptly declared and Frisk looked up, beaming once more. They held out the pie, hoping that Undyne would understand without them signing. She scooted to one side of the couch and Frisk sat down next to her and solemnly handed her a fork. “Thanks kid,” Undyne said as Frisk set the pie between them. Frisk let Undyne try it as they started fiddling with the remote, taking it off mute and finding a show with the robot from the night before. Undyne made a faint noise of disgust and on a guess, Frisk flipped the channel again and found an anime. A girl was shouting about the moon or something before she turned into a rainbow and changed her clothes. It seemed silly to Frisk but Undyne was suddenly watching it intensely as she munched a forkful of pie.  
“Woah Sans CAN cook,” Undyne muttered and Frisk nodded sagely. 

.:Dad’s the coolest,:. they signed, .:he can do anything!:.

“Yeah?” Undyne said. She seemed amused but Frisk wasn’t sure why. 

.:Well he made me a monster:. Frisk signed, .:no one else could have done that.:.

Undyne just laughed heartily and grinned. “Well duh! He’s your dad!”

Frisk got a forkful of filling and stuck it in their mouth. They noticed that Undyne was eating the crust instead of the filling and they frowned. They stuck the prongs of the fork between their teeth and signed, .:do you know where Dad went?:.

“Yeah, he SHOULD be with Paps watching for a human but I think he went to Hotlands to meet the human that’s already here-“ Undyne paused when she noticed that Frisk had gone completely rigid. “Er, I mean that’s, like, MY Sans. Your Dad went into the back room.” Frisk nodded. He must be working. He got really wrapped up in whatever he did. Frisk didn’t think that he wanted anyone to know about that, it wasn’t until he was their kid that Sans was happy to let them see his projects. He must have just wanted to let them sleep while he was working and lost time.

He still could have checked on them. Frisk swung their legs and hummed faintly, wondering if there was a way in without teleportation. 

“So, uh, kid?” Undyne asked. Frisk hummed curiously as they leaned forward to look at her face. Her brow was knitted tightly and she was frowning. “I know that you skeletons are weird about your names – I remember back when Sans wouldn’t talk Paps insisted everyone call him ‘Baby Brother’ until we learned his ‘font’. But, uh, with that in mind. Is there like, a nickname you want me to use? Unless you like being called ‘punk’.” 

There was a length of silence before she finally looked down at Frisk and was surprised by how elated the kid looked. It was as if Undyne hand just handed them a sack of chocolate. “You remembering to breathe there, kid?” Undyne laughed as Frisk bounced in their seat. 

.:Call me F-r-,:. Frisk paused as they stopped fingerspelling their name. For a moment they were so pleased to be called their own name that they forgot that there was another Frisk that Undyne knew. She had accepted their dad was a Sans but Frisk wasn’t sure how they felt announcing that they had been a human once. 

Undyne seemed to take the sudden pause as Frisk meaning they were done, and she wrinkled her rubbery face. “Fr? Like as in fur?” Undyne asked. Frisk lurched a little, about to sign something else but Undyne had already sprung off the couch, fists clenched and her head turned up as she cackled at the sky. “FR! HELL YEAH!” Frisk screeched as they were scooped up into Undyne’s arms and they wiggled furiously. “Short and sweet! A WARRIORS name! I love it!” She cackled before she set them down on the table. “It matches that stupid jacket too! AHAHAHAHA!”

Frisk looked at their jacket, it looked normal to them but . . . it was fluffy. Frisk found themselves grinning as they hopped on the edge of the table, their bones rattling. Undyne was so happy, and it was making Frisk happy too. They bounced a little on their knees before they jumped off the table and wrapped their skeletal arms around one of hers and Undyne spun them around happily. 

Frisk rattled their bones happily, though when they were put back down they were a little dizzy and wobbled on their feet. The pin-pricks of lights in their eyes swirled before Frisk fell down on their bum with a small ‘oomph’. They yelped at the unexpected feeling of their exposed tail bone hitting the floor and Frisk lurched up to their feet again. They were still unused to the feeling of some of their exposed bones interacting with the world nix their old cushion of meat. 

Undyne hadn’t noticed, she was many things but sensitive to minor scrapes was not one of those and for that Frisk was grateful. They still struggled with the need to hide weakness, but their father had drilled it into them before they left that to show any weakness – or to let another monster know of their weaknesses – was the same as tying themselves a noose. But this Undyne seemed so nice, and Frisk decided that Undyne might be able to help them.

They had magic that they didn’t know how to use. That they wanted to learn the basics of. 

Sans had said they would be human soon enough and that he would keep them safe in the meanwhile but even so . . . Frisk was a monster now and while Undyne wasn’t a skeleton they had overheard Papyrus saying that Undyne was a skilled teacher.

Frisk reached up and tugged on Undyne’s pants leg, demand her attention and not stopping until Undyne took a knee so she was making eye contact with them. “What’s up, Fr?” She asked and Frisk looked around the room conspiratorially. Undyne seemed to light up at the secretive behavior and she gave Frisk the biggest grin they had ever seen. 

.:Undyne, can you teach me how to use magic?:.

**Notes for the Chapter:**

> I know ever since the 'Paps would call Sans aniki' tweet the whole fandom has been obsessed with the idea that Sans is the older brother buuutttttt I've never really liked that. I love big brother Paps and baby brother Sans. :3


	9. The Pun is SkeleCAN, not SkeleCAN'T

**Summary for the Chapter:**

> Skeleton magic is explored

It wasn’t like Sans had meant to get distracted for so long. He could have sworn he was carrying Frisk up to bed no more than an hour ago, tucking them neatly in a pile of blankets and kissing their forehead before he ejected the blue version of himself and locked the door from the inside. When he did get to HIS lab he ran into his other self again, and this time they argued over who needed the machine more before Blue finally pissed off and left Sans to start calculations.

Now that he knew how, it wouldn’t be hard to alter the machine to punch another hole in space time but with how creepily pleasant everyone was Sans didn’t think he needed to set that up just yet. Not without fighting Blue for it and Sans wanted to avoid that. Which meant that his time and tools were better put to figuring out how to get Frisk’s powers back.

He came up with two ideas in the end. One he was certain would work yet would be met by opposition on the part of Frisk and one that probably wouldn’t work but would make Frisk happy regardless of failure. Sans ground his teeth, gold fang crunching hard into the fourth pen of the day and the weak plastic finally gave out, spurting and filling his mouth with blue ink.   
Sans gagged and hurled the pen to where the trashcan should have been (Blue kept his about a foot to the left so the broken pen bounced off the wall and landed sadly on the floor with the others in an expanding pool of ink) before he slammed his elbows onto the table and groaned in frustration.

Math was his thing. Physics. Spacetime. Unfaltering laws the universe followed Sans could twist and study to his own ends.

But souls? The power they held? This was no question he could solve with number crunching. He didn’t know how two souls of the same person could interact, he didn’t know if Frisk’s determination as a monster was at all capable of handling the determination of a human soul. There was no way to test it, except on himself but there was still only one living soul! Unless he wanted to go after one of Asgore’s stash and studied it without anyone in this world noticing.

Sans groaned and wiped his mouth before he glanced at the digital clock perched carelessly on a joke book.

2:34

He sighed. It had only been three hours but-

2:35 PM

Sans went rigid as the two letters flashed at him. No way. It had barely been midnight the last time he looked at the clock! With a snarl that was a mix of irritation and alarm Sans teleported to his room to find it … completely empty. He did spy Frisk’s clothing neatly folded on his bed and their shoes set next to a bed post but other than that . . . 

“Aaaaaah,” came a faint, slurred voice from downstairs. In a spark of red Sans was outside his door and met with … a very strange sight.

“NO! Not like that! Let me feel your passion! Scream from the very depths of your SOUL!” Undyne punched the air and took the deepest breath possible before she screamed, “AAAHHHHGGGGGGH!” The painting of the bone on the wall almost fell off but Sans unthinkingly caught it before it had the chance.

Undyne had turned the couch so it was resting on one side, sticking straight up into the air and Undyne herself was standing on the other end, hoisted high above the ground with Frisk sitting on their shoulders, both hands holding her hair so they wouldn’t fall off. In doing so, they much have pulled out Undyne’s hair tie because now it was splayed wildly about her shoulders and she had pulled off her tank top to use as a sweatband, keeping her hair out of her eyes.

“Ahhh,” Frisk tried again, a little louder but still uncertain. They hadn’t noticed Sans either, and he leaned over the banister to watch curiously. 

Undyne jumped, and the couch shifted so it was balancing on only a corner. “YEAH! Like that, Fr! Now make your SOUL resonate with your passion!! Shout with everything you have!” She took a deep breath, the red gills along her torso flared before she shouted again, and this time Sans could feel what she was doing and his eye flared red in response. He could see Undyne’s soul burning wildly in her chest as raw green magic arched out of her breast and to her fists in a display of raw power. It was unrefined, the sort of magic children used and Sans narrowed his eyes. What was she-?

Before Undyne’s magic had started to fade, Frisk straightened on her shoulders and raised their own tiny fists. Their own soul began to glow behind their ribs. “AH!” They pipped out, screaming as loud as they could manage and much to the shock of Sans, their eyes began to glow properly. Not the faint gleam of the night before but a distinct blaze of crimson forming a burning ring in their empty sockets as magic rippled over their skull.

Sans had always found the color of his and Papyrus’ magic to be aggressive and hateful. At a glance most people knew red was dangerous and the furious shade of the skelebros was usually enough to get weaker woes to back off. But … even with their eyes burning Frisk looked so open. So cheerful, so friendly. The shade was identical but it danced with mirth and warmth. Sans felt his knees start to weaken. He had been afraid that to use magic Frisk would have to be as fearful as himself or as spiteful as Paps but here they were … learning magic from their murderer with a look of pure delight.

Sans eased himself off the banister and finally settled his expression in his usual scowl. “hey,” he said. Frisk looked up, eyes still burning and Undyne waved. With a skill only before displayed by skaters and their smaller boards Undyne turned the couch expertly on a pivot before she sent it down exactly where it had been previously. She jumped in the air as she did so and landed neatly on one of the seats, Frisk now seated firmly on her lap.

.:Dad! Undyne was showing me how to use magic!:. Frisk signed and Sans couldn’t help but give them a genuine smile.

“oh yeah?” he asked and Frisk nodded sagely. He used a shortcut to get to the couch and he neatly plucked Frisk out of a startled Undyne’s grasp. “put your fuckin’ shirt on,” he grumbled and Undyne made a gesture with two fingers behind Frisk’s head before they untied their bandana and yanked it over her head. “well sweetie?” Sans said expectantly. Frisk’s pin pricks of light shimmered as they cocked their head until Sans elaborated, “don’t you wanna show me what you can do?” Frisk’s pin pricks lit up and they wriggled free. 

As soon as their feet were on the ground, Frisk dashed to the couch and stood on the back of it. Had . . . had Undyne told them they needed to be as elevated as possible or something? And if so why didn’t Frisk just use the stairs? “YEAH! Go Fr!” Undyne cheered. Sans looked at her skeptically but when she noticed Sans wasn’t encouraging his kid too she elbowed him roughly in the ribs. 

He coughed before he grinned at Frisk and said, “go on kid, it’s not like we gotta clean the damn place if ya fuckin’ wreck it.”  
“TRASH THE PLACE, FR!”

Frisk grinned. Apparently thoroughly encouraged and they threw back their head. Once again their soul began to blaze under their ribs and through the candy colored abomination they chose to wear. Frisk bellowed with everything they had in their tiny chest, though they were drowned out by Undyne. Red light flickered above their sockets and when they looked down again their eyes were blazing with powerful magic once more. Out of curiosity, Sans actually took a peak at their stats when Undyne wasn’t looking and he was actually impressed. Very impressed. Their stats were even better than his Boss!

Sans had never actually thought of magic as something that could be fun before and he shut his right eye as the left started to flicker and glow. His magic was always something that was rectory, something he used either to hurt or to keep from being hurt – the only exception being when he had brought Frisk back, and using his powers to manage them. But now, seeing the way Frisk and Undyne beamed with the manifestation of raw power, raw essence . . . “well? go on baby bones, lets see what you can do!” Sans said. Frisk looked at him, confused but enthusiastic as he formed a bone and balanced it on his index finger. 

“wanna see if you can do this too?” Sans asked and Frisk just about vibrated in excitement as Undyne whooped. He had work to do, and he needed to talk with Frisk about how to get their powers back but that was no reason not to have fun with his kid.   
.  
.  
.  
Sans carried the human carefully to his bed, using his magic to knock off the tangle of blankets before he laid them out on the bare mattress. There were some crusts of dried mustard fused to the cloth and a few springs poking up that didn’t bother him as a skeleton but might bother a meat bag. He ground his fangs as he laid them out, trying to make them look neat and comfortable. Their eyes stared blankly forward and tenderly he wiped a trail of drying blood from their lip with a boney finger. Aside from the shredded clothing and dead eyed stare Sans could almost believe that Frisk was just resting. 

“fuck, kiddo,” he grumbled. And to think, he had promised that old lady that he would kill the kid when no one else could. Sans leaned over them to shut their eyes before he heard the front door slam open and the sound of Papyrus storming in. Sans closed his eyes before he straightened up. They wouldn’t mind if their eyes were left open, not when they seemed as good as dead. “don’t worry about it, kid. i won’t tell him you’re here.” Not like when he had first found them in the forest. 

Sans slipped out of his room and edged to the bannister, his eyesockets empty even before Papyrus bellowed, “SANS!”

“yeah boss?” Sans asked. Papyrus snapped his head to look at him like some great predatory fish, all cold fury and spite. Sans felt his gold tooth pressing against the bone of his lower jaw and remembered when he was still a baby bones himself – back when Gaster had vanished and only Sans could remember him. He kept insisting that Papyrus had to know too, had to remember the labs and the tests when Papyrus had whirled on him with that same hateful glower. It had been another twelve years before Sans’ jaw finished growing and he was able to get a replacement for the tooth he had lost in Waterfall mud. 

Papyrus stormed up the stairs and Sans backed up into the wall, hunching his shoulders so his face was obscured by the fuzz of his jacket. “UNDYNE CAPTURED THE HUMAN, SANS, AND SHE TOOK THEIR SOUL TO ASGORE!”

“o-oh yeah?”

“SHE WALKED BY YOUR STATION WITH THE SOUL!” Papyrus shoved Sans’ shoulder roughly and the smaller skeleton felt the back of his skull slam painfully against the wall behind him. “YOU EXPECT ME TO BELIEVE YOU DIDN’T NOTICE THAT, YOU USELESS SHIT? AND NOW SHE’S GOING TO BECOME HEAD OF THE ROYAL GUARD AGAIN!” Ah. So that was why he was so furious Sans thought before Papyrus grabbed him by the front of his red shirt before he swung him around and threw him against his own door. Sans hissed as he slumped down to his arse as one of the hinges groaned and cracked the wood. Sans felt a sudden twist in his gut, something strange yet intense as the hinge slid out of place. 

“i was at the station in snowdin,” Sans lied through gritted teeth, “unlike the great papyrus i can’t be at three places at once.” He pulled himself up to his feet with a grunt and glowered up at his older brother. “besides, you’re the one who decided to let ‘em go n the first place, huh? maybe you should have been keeping a closer eye on them?”

That may not have been the smartest thing he could have said. Fury radiated off his brother like a heavy cloud and he summoned a bone attack club and he brought it sharply down at Sans’ head. He couldn’t dodge, if he did then the door would be split open and Papyrus would see Frisk. Instead, Sans turned his brother red and shoved him back to the bannister as the swipe of the club caught only the poof of his hoodie. Papyrus stumbled back but caught himself before he glowered down at Sans, now equal parts suspicious and furious. Before Papyrus had the chance Sans decided to lock himself in. 

He slid inside the doorway, lifting it as he did so in a way that made the hinge line up properly again before he closed himself off. The back of his skull throbbed and Sans didn’t doubt there was a new crack in the bone but he wasn’t nearly skilled enough in green magic to fix it himself. 

Sans stood silent, his hand resting on the door handle as he listened to the sound of Papyrus stalking around the living room before he closed his eyes and pressed his forehead against the splintery wood. What had he done? Why had he done it? To thoughtlessly defy his brother, his BOSS in such a way. Surely there would be repercussions once Papyrus stopped his raging and remembered that it was just Sans. Just a weak, one trick pony with the lowest stats in the Underground.

Maybe Papyrus would finally decide Sans wasn’t worth the effort?

“what the fuck did you do to me, kiddo?” San grumbled as he turned around, only to stop dead. Frisk … when he had left them their head had been staring up at the ceiling but now their head was turned and their blank eyes bored directly into him. A shudder ran down his spine before he realized that there must just be a lump in the pillow that made their head role. “fuck, kid, you tryin'a kill me before boss gets the chance?”

With one swipe of his hand Sans made sure that his door was locked before he pulled a chair up to the bed and straightened their head.

Why … was he doing this? He couldn’t leave their body splayed out in waterfall, especially since they were still technically alive but why then had he brought them here? He slumped in his chair and glowered up at the ceiling as well. Well, it didn’t matter. Asgore would absorb their soul and then they would be as good as dead. The King was going to slay every human, and with the powers of a god there would be no hiding Frisk from him.

Sans groaned and looked down again, only to jump in his seat. They were looking at him again! Their blank stare on his face and he could swear he heard a faint gurgling from their open mouth. Sans stared back, looking for any sign of emotion or spark of light in their gaze before he figured that it wasn’t real. They were empty now.

Sans closed their eyes with two gentle fingers.

He sat back, looking at them with mixed feelings.

They had no soul. They were empty. Yet still …

Sans’ eye sparked to life, bathing his room in a red glow. With his magic he reached to where their soul out to be, then reached in deeper. He felt for the sparks in their mind, electricity that went off without any messages to deliver. He felt the residue of DETERMINATION, their primal will to survive. He found the energy that powered their organs, their heart, their blood and he coiled his magic around it like a serpent around a rat.

Then he started to pull it upwards. Everything that made Frisk alive he pulled out, and as he did he felt their organs still, their brain grow silent, their cells pause their ceaseless shifting. The energy tried to disperse but Sans held it still, forcing it to where a soul should have been and balling it together.

His own soul was burning in his ribs, and Frisk was bathed in the light of everything he was. It was cold. It was hateful. But he felt something reach out for him gingerly, like one would reach out for a frightened alley cat.

All that was left of them had been gathered but it wasn’t enough. More was needed and Sans felt their energy brushing across his soul. Not stealing but copying, forming weak imprints that were drawn back into the energy he had collected, slowly giving Frisk shape and structure. It felt disgusting, having his soul touched and examined. Sans inexplicably felt filthy, like something vile and undeserving as his soul was gently opened. 

Then Frisk was pulling back, sinking back into formlessness and Sans tried even harder to hold them together. Now not only holding their energy but their imprints of his own magic together and mashing it ruthlessly into a single form. Even he was unclear on what he was attempting but now that he had started something deep in him was driving him on, forcing him to consolidate what he had gathered until finally…

There was a flash of red and white light in quick succession and Sans snatched his hand back as something new blossomed under his fingers.

A soul rested in Frisk’s chest. But not a human soul. A white, inverted heart with only the faintest hint of red at the rim floated over them, and Sans knew without knowing that it was Frisk.

Slowly, Sans let his soul fade back into him and Frisk’s did the same. He felt strange, sick and depleted but at the same time unusually protective.

“frisk?” He asked as he leaned forward. They didn’t respond and he shook them gently. “hey frisk, can you hear me?”

They twitched. 

Sans saw one of their fingers move. But not in the way it should have.

Then their arm raised and Frisk set it on their face.

Something was very wrong.

Frisk let out a muffled cry, though their lips didn’t move and they started to weakly struggle. They were moving of their own volition but it seemed unnatural. When their fingers moved the muscles and skin remained slack, being pushed around by the skeletal inside rather than the meat. The meat actually seemed to slosh around and it made Sans feel sick.   
It was like their flesh was a water balloon, weakening as their insides jellified as they were reformed by their monster soul. Humans had too much extra material, monsters were essentially formed hunks of magic and whatever Frisk was turning in to they didn’t need everything they had.

Under their skin, Frisk continued to writhe. They started to let out muffled cries, almost as though they were gagging on their useless vocal cords and they kept shaking their head, trying to see from behind their sightless eyes. One of their hands reached out and grasped Sans’ own, and they squeezed him so tight that dark seams began to run across their palm. Seams were running across all of their body, and Sans was struck with the memory of when he saw Alphys shed her skin. She had been agitated and kept squirming as her skin began to crack before it peeled and new scaled were revealed.

Sans yanked his hand out of theirs and sprang back as the seams on their flesh deepened before it ripped and seemed to pop, releasing a slew of semi-liquefied gore across his bed and onto the floor. Sans covered his nose and mouth in disgust and backed up. There were strange lumps of meat and thick blood and he reeled back, a dull horror twisting in his stomach. But before he could conclude that he had killed them, their skeleton sat up. It looked around, confused and curious and Sans stood still and silent as he watched them. Is this what he had looked like after Gaster made him? Sans couldn’t actually remember that part of his ‘birth’. 

Frisk finally turned to look at him, and he saw little flicks of light in their now-mostly empty sockets. Their face seemed to relax when they saw him and Frisk turned towards him fully before they gently set a foot on the ground. Then the other. 

Frisk stood out of the mess on the bed and on wobbly leg. Their gray-white bones were absolutely coated in blood and bits of things rolled out of their open ribcage. Sans noticed that the shreds of their clothing held some of their offal to their bones and he dully thought that the mess in their shoes would surely be sickening. He should have taken off their sneakers before he laid them down. 

Frisk made a sign that he didn’t recognize. Then they pointed at him, then themselves, and then the strange sign again before they cocked their head. “um?” Sans said. Frisk frowned as best they could with a perma-grin and they took a wobbly step forward. They splayed their finger bones and tapped their thumb at the side of their temple clumsily before they pointed more aggressively at him. 

“i really don’t know what-“ Frisk shook their head as they staggered forward again.

Frisk raised a hand to start to finger spell as they tried to take another step, but it became clear that they were unused to balancing on skeletal legs and their knees suddenly gave out. Before they had a chance to fall completely Sans was beside them, one hand behind their skull and the other behind their knees. “geeze, kiddo, you made a real mess. let’s get you cleaned up, how’s that sound?” They were silent, but there was a strange expression on their face. Sans felt a strange throb of something in his own SOUL, an emotion he couldn’t correctly identify. Whatever. He could figure it out later. He needed to get them cleaned up and dressed in non-human clothes before he did anything else.

**Notes for the Chapter:**

> If anyone wants to know what Frisk was trying to sign at Sans, it was 'Dad'.


	10. A Father's Love

“Papyrus did that to you, didn’t he?” Undyne asked.

Sans went rigid. He hadn’t heard her walking up to him but that kinda figured. Fish made no sound in waterfall. He hunched his shoulders and looked behind him without moving Frisk, or giving any indication he was holding them under water, despite the slowly expanding pool of red he stood in. She stood on the bank behind him in casual clothing and had a full view of the new crack on the back of his skull.

“yeah? well what did you expect? he worked all his life to be head of the royal guard and you took it away from him.” 

“I expect him to not take it out on his baby brother!” Sans sneered at her and let out a dry laugh. 

“have you met papyrus?” He turned his head away, looking back down at the skeleton in his arms. Undyne hadn’t spotted them and they seemed unaware that anything was amiss, aside from their weird compulsion to pretend to breath. 

“It won’t be like this anymore. After Alphy finishes examining that soul Asgore will absorb it. He will release us from our hatred once the humans have been killed and we reclaim the surface.”

“and you think that will change boss?” 

“If it doesn’t - if Paps never goes back to who he was before . . . then I will protect you from him. You have my vow as a warrior.”

“a warrior who kills children.” 

A gulf of silence stretched between them, and Sans subtly ran the balled up rag of Frisk’s shirt along the side of Frisk’s jaw, working off a particularly stubborn patch of dried blood. Mostly so they wouldn’t realize that Undyne was mere feet away.

“I can heal you,” Undyne said at long last.

“honestly i just want to be left alone,” Sans said truthfully. There was another pause before he heard her heavy footsteps leaving and slowly fade into the echoes of waterfall.

“fuckin hell,” he said, loud enough that no echo flowers would recall that little tidbit of Undyne’s voice before he finally lifted Frisk out of the water. “how ya feelin’, kiddo?” Sans asked as the tiny skeleton glowered at him. For the first time, Sans noticed that had a reddish tint under their eyesockets, a feature that Sans had considered unique in himself for the longest time. Well, maybe it was actually a common trait and Papyrus was the weird one for not having it.

.:You tried to drown me!:. they signed furiously, once again addressing him with the strange sign. Sans snickered and turned in the water before he started walking them to the shore, leaving behind a wake of gory water and their tattered clothing to float downstream. Once it made it to the dump no one would be the wiser. 

“what is that sign, anyway?” Sans asked, and Frisk looked at him in confusion. “oh come on, don’t fuckin’ play dumb i know you’re a smart cookie.” He set them on the bank and climbed out of the water himself. Ugh, wet and muddy slippers were not something he was particularly fond of. 

He looked down at Frisk, and frowned at their bare bones. With a sigh, sans peeled off his jacket and knelt, putting Frisk’s arms through it and zipping it up. It looked like some kind of stupid, oversized dress. .:d-a-d:. Frisk finger spelled at him and Sans cocked his head.

“what? kiddo, you know that’s not my na-ooohhh.” Frisk looked very sincerely concerned when Sans suddenly blushed scarlet. 

They couldn’t really recall what Sans had done to them but deep in their newly formed Soul, there was a bond that was so inherent and exclusive to monsters. He was their dad. The memories they had of their human father were vague at best; a tired faced man, a man who had never wanted a child and when their mother left he had been stuck with them. He had been their father in a technical sense – and he would always be their father – but Sans was their dad. 

.:Yeah, you’re my dad,:. Frisk affirmed. 

Sans was giving them a funny look and he rubbed the back of his neck sheepishly. The look on their face was so honest it was making him feel uncomfortable. His dad was Gaster, and he was frankly an asshole. And that had been before the underground had become so angry and hopeless! The idea of having that authority upon him after years of avoiding it should have made his stomach churn. He should be telling Frisk off for calling him that but . . . “well, if that’s what you want to call me then i guess that’s that.”

Frisk grinned like it was Christmas morning and Sans felt like he was going to cry. “uh, anyway. we gotta figure something out – since you haven’t done it yet i’m assuming you can’t reset?” Frisk shook their head. “glorious. lets get home and figure out what to do.” Sans picked Frisk up and slung them onto his back, and without Being told Frisk nestled in. He looked lumpier than usual but at a glance Sans looked like he was wearing his hoodie and not carrying a kid with their face nestled against the back of his neck. 

He decided to walk back to Snowdin with Frisk on his back. They were silent but it felt good. Right in a way. He wanted to delay seeing his brother, yes, but more than that he just wanted to keep them safe.

Still, eventually they reached the dense fog where hot waterfell air met the cold snowdin water and Sans put his head down. His shoulders slumped as his house came into view. He felt impossibly small as he reached out and turned the door handle. He could hear Papyrus inside, stalking like a wild cat ready to pounce. 

“THERE YOU ARE YOU USELESS SHIT!” home sweet home, Sans thought as he ducked to avoid a plate that had been hurled at his face. Papyrus loomed over him, furious and hateful but for once Sans didn’t back down and slink away. He couldn’t.  
“DID YOU SNEAK OUT YOUR WINDOW LIKE A PINNING BITCH? UNBELIEVABLE!”

“lay off the cursing,” Sans grumbled but it was too soft for Papyrus to hear. 

The larger skeleton gestured wildly and furiously as he ranted, “YOU WERE ALWAYS USELESS BUT NOW YOU’VE PUSHED IT TOO FAR. YOU COST ME MY JOB, MY REPUTATION! I AM SICK AND TIRED OF CARING FOR YOU, LAZYBONES! DO NOT WASTE MY TIME WITH YOUR PRESENCE AND LEAVE MY HOME!”

Sans glared, wondering for a moment if Papyrus really had forgotten who paid for their house. “DON’T GIVE ME THAT LOOK! I HAVE PROTECTED YOU FOR YEARS AND THIS IS HOW YOU REPAY ME? YOU SHOULDN’T HAVE COME BACK HERE!” Sans barred his teeth and the red light in his eye sparkled dangerously off his golden tooth. He didn’t notice his eye had lit up until he saw the faint reflection of red off the metal spikes on his brother’s jacket. 

He felt Frisk shift on his back, and suddenly Papyrus lurched back. His brother looked affronted, surprised even as Frisk stared at him with curious eyes. They slipped from Sans’ back and took his hand as they stood beside him and basked in the comfort of his presence. 

“SANS WHAT THE FUCK,” Papyrus said. 

“stop cursing!” Sans snapped. He squeezed Frisk’s hand before he cleared his throat. He wasn’t a big fan of telling his brother off, he wasn’t much a fan of getting his skull cracked either. “Boss . . . this is my . . . child.” 

“WHO-“

“doesn’t matter,” Sans cut him off, “this is my kid. they haven’t started speaking yet so they don’t have a name.” Papyrus had been backing off and he sat down heavily on their ugly couch. “you can’t touch them, okay? if you try to hit them . . . i . . . i will hurt you, papyrus.” Frisk tugged on his hand, but Sans refused to look away from his brother. 

Papyrus cocked his head and glowered. “YOU WILL HURT ME?” Papyrus asked. Sans nodded but Papyrus just laughed. “YOU BRING HOME A CHILD AND THREATEN ME? YOU THINK THIS IS WHAT A FATHER OUGHT TO DO? SANS, BRING MY NIECE – NEPHEW? BRING MY NIEPHEW OVER HERE!” 

“what.” 

Frisk lit up, and they darted over and dove into the couch beside their uncle. “ woah, wait, no. no no no!” Sans bristled and he stalked over himself. But to his surprise, Papyrus scooped up Frisk and held them over his head. 

“I SEE YOU RESEMBLE YOUR FATHER. THIS IS UNFORTUNATE.” Papyrus touched the red rim of their eye sockets and Frisk giggled. “WORRY NOT, AS IN ALL THINGS MY BIOLOGY IS STRONGER THAN MY BROTHER’S, YOU WILL NO DOUBT GROW TO RESEMBLE ME. YOU SHOULD BE GLAD OF THAT FACT, LITTLE NIEPHEW!” He tossed Frisk into the air and caught them. Sans felt extremely uncomfortable with this, he had never seen his boss so friendly. 

“DO YOU LIKE PASTA, BABYBONES? WOULD YOU LIKE TO COME WITH ME TO GRILLBY’S?” Papyrus asked and Frisk lit up. They nodded but Sans picked Frisk out of his brother’s arms. 

“okay well as touching as that is i actually need to take care of my kid. i only stopped by here to get some stuff before i take them to get an examination,” Sans sat them on his hip before he turned to stalk up the stairs. Sans was uncomfortably aware of the disappointment on Papyrus and Frisk but he was uncomfortable leaving his . . . his child in the company of the skeleton who had been abusing him since the moment Gaster vanished. Especially with how friendly the Boss was being, it made Sans’ teeth itch. 

And Frisk? Well they saw the good in monsters. Only the good in monsters. Even monsters like Papyrus. 

Sans kicked open his door and took a shortcut into his lab before Frisk could see the ruined patches of their body strewn across his bed and floor. He needed to figure some shit out, but first he needed to work on his escape route.

**Notes for the Chapter:**

> why the flashback chapter, Tubbs??? why not moving on the plot???????????
> 
> ¯\\_(ツ)_/¯


	11. Melt Back

**Summary for the Chapter:**

> WARNING   
> there's a warning in the tags for child abuse but I'll warn you again, mentions of physical and sexual child abuse.
> 
> Other than that, Frisk decides what to do next!

Sans was not A Fan of Grillby’s. It was the Boss’s place, where he went to bark orders and get his food and the place had always been his.   
Besides, the joint was too classy for Sans. At least that was what the real fire elemental who manned the counter seemed to think. When the first came to Snowdin, Sans had used his first paycheck to try to get some fries from the place and Grillby had taken it as a personal offense. Sans had been unofficially banned ever since.

Sans had slunk in for food since between Frisk and Undyne there was nothing edible left in the house and as low as his HP was, Sans liked to try to keep it above maximum. Best way to do that was food and sleep and there was no time for the latter. It had taken more convincing than he liked to get Frisk and Undyne apart (he really needed get them to slow down with this befriending everyone thing) before he walked into Grillby’s with all the cheer of a man walking to the noose.

He wasn’t sure exactly what freaky Grillby’s would be like but he did not expect a bell on the door to chime pleasantly as he was met with a blast of comfortably warm air. Sans stepped in, holding Frisk’s hand and he glanced around. 

What the fuck.

This place looked like some Gotland diner! More like that stupid restaurant Metaton ran than Grillby’s snazzy place. It smelled like warm, greasy food and spilt beer - and while the Royal Guards were there it was clear that the atmosphere was light and welcoming.

And all at once people started greeting him. Casually. By name.

“Hey Sans! Who’s the kid?”

“Woah, Sans, I take back what I said about you sleeping too much. You feeling okay, buddy?”

“Those teeth sharpening kits actually work?” 

“Hey there little guy, what’s your name?”

Sans held Frisk closer as he matched the monsters he was seeing with the monsters he knew. “uh, hi,” he grumbled at the people who greeted him, and when someone made a joke about his eating habits Sans glowered at them until they coughed nervously and looked away.

He sat Frisk down a barstool, using his jacket to hide their rainbow vomit clothing before he slumped into the chair beside them. They looked like they were enjoying all this.

“hey we talked about this,” Sans said as he gently elbowed them, “you gotta look tough.” Frisk looked skeptical but they stopped wildly swinging their legs and folded their arms on the table just as the man himself walked up.

Sans wouldn’t have recognized him at all, outside of the fact that both of them seemed to like the formal suit vest and bowtie look. This Grillby was a cheerful shade of orange and the heat he radiated was comfortable and soothing. Everything about him put Sans on edge and Frisk tried to brood at him.

“Hello Sans, your usual?” The flame asked in a voice like crackling wood. 

“no,” Sans said, god only knew what bizzaro Sans liked eating, “gimmie a bottle of mustard.” Grillby flickered purple in surprise before he reached down the bar and slid over a plastic yellow bottle. Sans caught it and used his gold fang to puncture the end of it so it would pour easily.

“And for you?” Grillby asked.

.: Hamburger and fries!:. Frisk said, failing very badly at brooding. Sans stiffened at the request but Grillby just nodded and vanished into a door of fire a little ways down. 

Sans relaxed a little before he glared playfully at Frisk. “a hamburger? kiddo, you betray me. i thought hotdogs were your favorite.”

Frisk nodded sagely, .:they are my favorite, but only when you make them. No one else does it right.:. 

Sans blinked.

He blinked harder.

That was the nicest thing anyone had ever said to him. It was only years if social coding that prevented him from scooping them up into a hug. Instead he reached out and ruffled the fuzz of his hoodie, where it shrouded their skull in imitation of hair.

Grillby was back all too soon, and he set a steaming plate in front of Frisk. They lit up and started munching on fries, oblivious to the heat without skin to feel it. Sans was also failing at brooding now, and the affection in his empty sockets seemed to have caught the attention of every monster in the bar. The royal guards seemed to have returned to what they were doing, same as the rest of the monsters in the booths. But the bar was a different story.

“Hey Sansy, who’s kid is that?” A rabbit at the bar eventually asked. She leaned in a little too close and Sans was tempted to shoot a bone attack at them.

“they’re my kid.” Sans said.

“Whaaaaaaaaat? Where have you been hiding this!?”

“Well it’s about time we had a new face around here!” 

“Oooohhhh, I can see the resemblance! They have your eyes.”

“So did you name them?”

The ruckus at the bar grew and grew until every monster in the restaurant had heard that the skeleton with Sans was his child. Sans sat rigid and horrified as every monster in the world seemed to want to congratulate him. He was unused to any sort of positive attention, much less this much of it! Someone stuck a cigar between his fangs and someone else lit it and a very excited dog was thumping his back and barking about ‘pups’. Someone was asking what babybones liked for toys and that oh, surely they could bring a new bed by their house! It would be there before the end of the day – Bonnie had SEEN the state of Sans’ room and he only had one mat that BARELY counted as a bed to begin with. 

Sans felt like he met every monster in Snowdin by the time the monstered pissed off and they were allowed to sit at the bar in peace. .:Blue-you will kill you when he sees you let them turn his room into a room for me:.

“he can try,” Sans grumbled irritably. 

Frisk’s food had long sense grown cold but they munched away regardless as they looked around the now empty bar. Frisk liked how happy everyone seemed at the sight of them and they were even humming softly under their breath. Sans wanted to go back home but there would surely be townsfolk all over the house and he needed to not look at blueprints for a while.   
Sans scooted closer to Frisk, and stole a fry off the edge of their plate, slathering it in mustard before Frisk had the chance to demand it back. “ugh, so kiddo,” Sans said as Frisk finally sank their teeth into their hamburger. “i think I have some ideas for how to . . . get your powers back.” Sans lowered their voice as he looked around.

Frisk nodded and Sans continued, “so first, we could do what undyne did to you and-“

Frisk slapped their greasy hand over Sans’ mouth and glared at him, reddish tears already forming in their eyes. Sans coughed slightly. Well, he had expected that in all honesty, but he hadn’t expected the immediate sinking guilt. Sans put his hand on their wrist and gently pulled their hand from his jaw.   
“okay, okay. we won’t go with that one, sweetie, i just needed to throw that out there.” Frisk glared at him again before they turned back and started eating their now flattened burger. “alright, yeah but this one you’ll like more. the other way this frisk could possibly use their powers is if we get them the ending they want. without anything to fuel their determination you might just inheret their abilities.”

Frisk paused mid bite before they began to chew thoughtfully. They were silent for a long enough time that Sans started to worry that he had offended them again. Frisk was in silent thought while they finished their meal, and Sans ended up going through seven bottles of mustard just to ease his nerves. He was determined to keep going until a small, greasy hand tugged on his red sleeve.

“hm?”

.:Hey, dad?:.

“hmm?”

.:I think . . . that I don’t really need my powers back. I think I’m happy. If I become human again then I lose all this. What I want to do is help this Frisk save the world.:.

Sans furrowed his brow and turned on the stool so he was fully facing them. He rested an elbow on the counter and used one hand to prop up his chin. “you want to give this frisk a good ending,” it was a statement not a question but Frisk still nodded. Sans sighed and rubbed the vertebra of his neck.

He should tell them this Frisk wasn’t them, and that they ought to take what should be theirs by right.

But…

But that wasn’t something Frisk would want. That wasn’t something Frisk would do. 

“well, i can’t say i’m really surprised. but, uh, you know. if you never get your powers back that’s it for our world. all humans dead and monsters ruled by a vengeful god. is that something you can live with?”

Frisk looked down at their empty plate and frowned. Oh. That.

Frisk was so used to thinking of the problems of their world as resettable that they hadn’t really considered that this was it. That world had been cemented in that path without them there to start it all over.

The humans were dead.

Their family was …

Something dark seemed to stir in their bones. It crept up their spine and into their thoughts, tainting it like rot in a stream. It twisted their memories into one singular emotion: satisfaction.

They were satisfied with the outcome of that world.

They could remember clearly the say their father strapped them into the back seat of their old four door. He buckled them in a little too tightly but he had a cigarette between his lips. Frisk knew not to say anything to him when he was smoking. He drove for miles and miles, out of the muggy wetland Frisk called home and into plains of yellow grass that moved like an ocean in the wind. And on he drove into a town in the shadow of a mountain and into the darker shadow of the white house with green shutters.

Their father had gotten out of their car as their aunt stormed out of the house. Through the open window Frisk had heard everything. Their father plainly saying he didn’t w a n t them, they were ruining his life and he couldn’t take it. Their aunt countered that she had no room for another child, that she didn’t want Frisk either.

But eventually Frisk had been led out of the car and into the house.

Their father didn’t make eye contact as he got into his car and drove away.

Their cousin hated them the moment she saw them. She hated them for not speaking, and more so she hated them because when they arrived her own father stopped looking at her with what a child would think of as affection. Their cousin didn’t like being ignored or beaten and they lashed out to the one person weaker than herself.

And their uncle… he had adored them. He had brought them toys and candies and said they were so beautiful that he needed to film them at all times. Playing in the back yard, eating at the breakfast table as their aunt yelled to put that damn thing away, when Frisk went into the tub and washed their hair, from a chair in their bedroom as they changed into their pajamas.

Then at times he looked disgusted, he would rage at them and take off his belt. One the metal clipped their face and tore it, and then he had gone and bought them a necklace with a real diamond to make it up to them. They could recall their aunt walking in on their uncle with his hands on them and she had blamed Frisk. She had chased them out of her house, past the grinning face of their cousin and into the road. 

Frisk remembered all the black eyes and cuts no one questioned, Frisk remembered how the people they tried to tell brushed them off. Frisk remembered feeling like they were less than nothing, they were a burden to the world itself and they owed the world, that it was deserved.

And they were satisfied.

In one world they were gone.

In one world they couldn’t hurt them.

‘I am glad,’ the poison chanted, 'they are gone and I am here.’

But the thing about poison is that it spreads, and it damages. The dark that had welled up in them curled warmly in their mind, and it casually reached out, tainting them with wickedness. The beast in their thoughts was comfortable and it began to purr. 

'I must be bad,’ Frisk thought, 'I am being so selfish I must be bad, worse than every living thing on this earth and below it.’ No good creature would destroy the world to soothe their heart and yet … The self loathing couldn’t make Frisk want them alive again.

“sweetheart?” Sans asked gently. He put a hand on theirs and Frisk realized they were trembling. How long had they been silent? Frisk didn’t know, their memories seemed to play out in real time, but they couldn’t have been sitting there for so many years. “hey it’s okay, i didn’t mean to upset you.” 

He would hate them. Their dad said kindness was a weakness but Frisk knew he admired that part of them. If he knew how bad they were he would hate them. Frisk deserved to be hated, and Sans deserved to know but … The words wouldn’t come out.

Anyone else. They could live with anyone else. Everyone else could hate them and Frisk would be fine. They world could want them dead and Frisk could carry on. But not Sans. Frisk knew they couldn’t live if Sans hated them too.

So instead of their fingers pouring out why they didn’t want their powers, why they didn’t want to go back, all Frisk signed was a quick .:I’m so sorry.:. 

They let their hands fall and Frisk looked down as they balled up their hands. Red tinted tears welled up in their eye sockets and began to drip on the table. 

After a moment Sans was around them, his arms curled around their ribs and one hand tucking their skull under his. Frisk clung to his shirt and let out a soft wail as he picked them up delicately.

Frisk was vaguely aware of him handing money over to a stunned Grillby before he carried them outside and into the cold air of Snowdin.  
All Frisk cared about was that he was there, and that they were never letting go.

**Notes for the Chapter:**

> This probably sounds weird, but part of the things Frisk had happen to them happened to me irl. The way they remember the past is the way that many people recall child abuse, myself included. 
> 
> Aaaaahhh, guess what I'm saying is this was pretty cathartic to write.


	12. The Actual OTP

When Sans walked into his room, to say he was surprised would be putting it lightly. Mostly because he didn’t actually walk into HIS room.

For a second he was wholly convinced he had somehow taken a shortcut by accident and he stepped back into the hall and shut his door. But when he opened it again he was still presented with a very uniquely unSans-y bedroom.

The walls had new wallpaper thrown up, apparently all gathered from the dump because it was a strange patchwork of images spattered everywhere; cuddly animals and flowers plastered up along with fighting robots, posters of humans in brightly colored uniforms, and one oddly misplaced poster of a skeleton holding guns. The image looked like it was something that was meant to be threatening but it wasn’t, it just looked rather silly. 

Sickly sweet air freshener had been hung up at random to cover the mildew smell that wafted up from the checkerboard rug that had been thrown over the carpet. His bed had been stripped too. Where a ball of sheets had been was instead a set of bubblegum pink linens and plush pillows from the Bunny family hotel. 

And the toys. 

On every surface there were toys. Rawhide bones, tug-o-war chew ropes, a squeaky carrot, a few strange looking monster plushies, a new copy of Fluffy Bunny…

It took a while for Sans to see his stuff, treadmill and a new futon nearly shoved into the corner along with his dresser. Sans neatly picked his way across the room, tip-toeing on his slippers in case one of the child-friendly toys might rear up and bite him. Hell, the place had more books and toys than Papyrus’ room!   
His stuff was actually very well organized in the corner it had been shoved in. The faintly dog-scented futon even had his old sheets, only made out neatly. He shuffled around his cabinet, making sure that the key to his lab was still in place and that the few files he read in his room were still all there. And they were, just now very unorganized as though they had been dropped then hastily shoved back in by someone who couldn’t read wing ding numbers. He sighed as he put the files back into place before he turned to gaze at the room once more.

“i’m going to kill him,” Sans said. 

He stepped into the hallway again and closed the door before he set his forehead against the smooth wood with a groan. He had his hands full already dealing with the human, he did not need both his lab and his room invaded as well.  
And how had the other him even done all this? His dinner with Frisk hadn’t taken THAT long… well, he had stopped to talk to Alphys about her opinions on alternate realities – though she knew the theories she specialized in biology and souls. Then he had gone to collect payment from his hotdog stand before he went to pay his and Papyrus’ taxes to the king. . . And then he had taken a nap on the riverman’s boat and ended up sleeping through five trips around the underground. Still, that was hardly enough time for not-him to rearrange his bedroom.

“Ha! You’re back, punk!” Was all the warning he got before his feet left the ground and he found himself tucked under a blue slimy arm. He looked up to a wide grin before he pointed woefully at his bedroom door. “I know, right!?” Undyne hooted, “They went to Grillby’s and the whole town was SO PUMPED to hear you had a kid! The Royal Dogs wanna add on another two rooms to the house to make more space! But right now Fr and their dad live there so-” Undyne hoisted him up before she hoped onto the banister. Whether it was as a display of grace or to unnerve him Sans couldn’t say but he went limp.

“You could crash in Papyrus’ room or-” Undyne took a leap and Sans grabbed the side of her shirt even though there wasn’t a chance she would drop him. She landed easily on a sink in the middle cushion, one that was distinctly Undyne-foot shaped before she dropped him on the seat next to her and struck pose. “You could crash HERE with ME!”

Sans turned himself so he was sitting and he folded his hands on his empty belly. “hmm? i think it’s more like you’ll be crashing here with me. it’s still my house,” he reminded her. 

“Aw, that’s just semantics! C’MON!! It’ll be like when we were kids!” Undyne laughed before she sat down hard enough that Sans bounced a few inches into the air. She slung her arm around his shoulder before she ruffled the back of his skull fondly. She never rough housed him the way she did with papyrus, for Undyne this was gentle and to be fair she would never do anything that might knock of a HP. He couldn’t really relate his interests to anyone outside of Alphys and, on the rare occasion, Grillby after half a bottle of whisky, and he had absolutely no real respect for the fact that she was his boss but . . . despite all that they were still friends. They would be friends even without Alphys or Papyrus – although those bridges certainly helped. 

He put his hand on her face and shoved her away before she decided to bite him. “yeah, yeah, a sleepover,” he agreed. It sounded fun, he guessed. “we can watch anime and talk about cute girls and-“

“YEAH, RIGHT. What do you know about girls!?”

“i know if i invite alphys to sleepover too-“ A large cushion made contact with his face and he snorted in amusement before he set it on his lap. Undyne’s ears were flushed purple at the tips and her lips were a thin line. And after all he had done to help her write a love letter? “you wound me, ‘dyne.”

“hey, actually,” Sans said as he leaned back, “that letter you wrote was really good. you gonna give it to her or . . .”

Undyne flushed and ducked her head, “well, I mean. She’s been pretty busy and stuff. And I don’t really wanna go to Hotland right now so-“

“want me to take it?”

“NO.”

“…want pap to take it?”

“N-nnnggg. No. You two are - . . . it would have to be someone else. Someone neutral on it,” Undyne said. Sans squinted at her.

“yeah? undyne, no one in the underground doesn’t know how you feel. except alphy.” He stretched out a leg and prodded at her thigh. She wasn’t looking at him and she was blushing hard. Sans slouched so his hoodie covered his lower jaw and he buried his hands in his pockets. “i mean . . . aside from . . . the human?”

There was a long stretch of silence.

“Yeah?” Undyne finally said. Her face crinkled for a second before she suddenly sprang to her feet. “YEAH! YYYEEEEEEAAAAAAAAH! Where’s Papyrus!? I need to call them!” Undyne sprang to her feet and looked around like the tall skeleton might be in the woodwork before she dashed off.

“yay, go get her,” Sans cheered mildly as she bolted from the house to hunt down Papyrus, likely at one of his many puzzles.

**Notes for the Chapter:**

> This chapter is mostly to give a sense of where Frisk is in their playthrough; out of the core and they beat Asgore once. The previous chapter took place before the 'go befriend Alphys' reset.
> 
> I'm a big fan of Sans - Undyne friendships too.


End file.
